U.S. patent application number 14/666948 was filed with the patent office on 2016-08-11 for method for photodepositing a particle on a graphene-semiconductor hybrid panel and a semiconductor structure.
The applicant listed for this patent is NATIONAL SUN YAT-SEN UNIVERSITY. Invention is credited to Chun-Hu CHEN, Cheng-Chi KUO.
Application Number | 20160233093 14/666948 |
Document ID | / |
Family ID | 56566134 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160233093 |
Kind Code |
A1 |
CHEN; Chun-Hu ; et
al. |
August 11, 2016 |
METHOD FOR PHOTODEPOSITING A PARTICLE ON A GRAPHENE-SEMICONDUCTOR
HYBRID PANEL AND A SEMICONDUCTOR STRUCTURE
Abstract
A method for photodepositing a particle on a
graphene-semiconductor hybrid panel is disclosed. The method for
photodepositing the particle on the graphene-semiconductor includes
providing a graphene-semiconductor hybrid panel, dipping the
graphene-semiconductor hybrid panel in a fluid containing a
precursor, and irradiating the graphene-semiconductor hybrid panel
using a light source until the precursor has been reduced or
oxidized to form a particle photodeposited on a surface of a
graphene sheet. The graphene-semiconductor hybrid panel includes a
semiconductor substrate and the graphene sheet adhered to the
semiconductor substrate. The light source has an energy equal to or
higher than a band gap of the semiconductor substrate. As such, the
particle can be directly deposited on the surface of the graphene
sheet without the need of modifying the graphene.
Inventors: |
CHEN; Chun-Hu; (Kaohsiung,
TW) ; KUO; Cheng-Chi; (Kaohsiung, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL SUN YAT-SEN UNIVERSITY |
Kaohsiung |
|
TW |
|
|
Family ID: |
56566134 |
Appl. No.: |
14/666948 |
Filed: |
March 24, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B82Y 40/00 20130101;
H01L 21/0262 20130101; H01L 21/02664 20130101; G01N 33/54373
20130101; H01L 21/02527 20130101; H01L 21/288 20130101 |
International
Class: |
H01L 21/288 20060101
H01L021/288; G01N 33/543 20060101 G01N033/543 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 9, 2015 |
TW |
104104224 |
Claims
1. A method for photodepositing a particle on a
graphene-semiconductor hybrid panel, comprising: providing a
graphene-semiconductor hybrid panel comprising a semiconductor
substrate and a graphene sheet, wherein the graphene sheet is
adhered to a surface of the semiconductor substrate; dipping the
graphene-semiconductor hybrid panel in a fluid, wherein the fluid
contains a precursor; and forming photoinduced electrons and holes
in the semiconductor substrate by irradiating the semiconductor
substrate using a light source, until the precursor has been
reduced or oxidized to form a particle photodeposited on a surface
of the graphene sheet by the photoinduced electrons or holes
transferred to the graphene sheet, wherein the light source has an
energy equal to or higher than a band gap of the semiconductor
substrate.
2. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 1, wherein
the graphene sheet is made by chemical vapor deposition and wet
transfer.
3. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 1, wherein
the semiconductor substrate is made of titanium dioxide or zinc
oxide.
4. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 1, wherein
the graphene sheet is formed of a graphene layer or a plurality of
graphene layers.
5. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 4, wherein
the graphene sheet is formed of three graphene layers.
6. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 1, wherein
the particle is made of metal, alloy or metal oxide.
7. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 6, wherein
the particle is made of gold, silver or manganese dioxide.
8. The method for photodepositing the particle on the
graphene-semiconductor hybrid panel as claimed in claim 1, wherein
the graphene sheet is made by chemical vapor deposition and wet
transfer, wherein the semiconductor substrate is made of titanium
dioxide, wherein the graphene sheet is formed of three graphene
layers, and wherein the particle is made of gold.
9. A semiconductor structure made by the method for photodepositing
the particle on the graphene-semiconductor hybrid panel as claimed
in any one of claim 1-8, comprising: a semiconductor substrate; a
graphene sheet having a first surface and a second surface opposite
to the first surface, wherein the first surface of the graphene
sheet is adhered to the semiconductor substrate; and a particle
deposited on the second surface of the graphene sheet.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a method for
depositing a particle on a graphene-semiconductor hybrid panel and
a semiconductor structure and, more particularly, to a method for
photodepositing a particle on a graphene-semiconductor hybrid panel
and a semiconductor structure.
[0003] 2. Description of the Related Art
[0004] Graphene is a light-weighted material with high hardness,
high carrier mobility, and high heat conductivity. Hence, the
applications of graphene are highly expected after it has been
successfully produced. Depositing particles on the surface of
graphene may result in further improvement of the utility of
graphene. For example, the graphene having gold particles deposited
on its surface is capable of detecting biomedical targets, such as
DNA and viruses.
[0005] However, according to a conventional method for depositing a
gold particle on a surface of a graphene, the gold particle can
only be deposited on a modified graphene, such as a graphene having
a functional group on its surface. The modification process is
inconvenient, and the gold particle still has to be deposited
through complicated chemical reactions. Since the gold particle is
bonded to the functional group instead of directly bonded to the
surface of the graphene, the adhesion of the gold particle and the
graphene is weak, and may easily be broken by an external force.
Furthermore, because of the modification site is located randomly
on the surface of the graphene, the deposited gold particle may not
be exactly on the charge transfer site, which results in a low
charge transfer efficiency. Moreover, the charge transfer
efficiency may further be reduced by the functional group located
between the deposited gold particle and the surface of the
graphene. As such, the utility of the gold-deposited graphene is
limited.
SUMMARY OF THE INVENTION
[0006] It is therefore the objective of this invention to provide a
method for photodepositing a particle on a graphene-semiconductor
hybrid panel for directly depositing a particle on a surface of a
graphene without the need of modifying the graphene.
[0007] It is another objective of this invention to provide a
method for photodepositing a particle on a graphene-semiconductor
hybrid panel for precisely depositing a particle on a charge
transfer site of a graphene.
[0008] It is still another objective of this invention to provide a
semiconductor structure having a particle directly deposited on a
surface of a graphene.
[0009] The present invention provides a method for photodepositing
a particle on a graphene-semiconductor hybrid panel, including
providing a graphene-semiconductor hybrid panel, dipping the
graphene-semiconductor hybrid panel in a fluid containing a
precursor, and irradiating the graphene-semiconductor hybrid panel
using a light source till the precursor has been reduced or
oxidized to form a particle deposited on a surface of a graphene
sheet. The graphene-semiconductor hybrid panel includes a
semiconductor substrate and the graphene sheet adhered to a surface
of the semiconductor substrate. The light source has an energy
equal to or higher than a band gap of the semiconductor
substrate.
[0010] In a form shown, the graphene sheet is made by chemical
vapor deposition and wet transfer.
[0011] In the form shown, the semiconductor substrate is made of
titanium dioxide or zinc oxide.
[0012] In the form shown, the graphene sheet is formed of a
graphene layer or a plurality of graphene layers.
[0013] In the form shown, the graphene sheet is formed of three
graphene layers.
[0014] In the form shown, the particle is made of metal, alloy, or
metal oxide.
[0015] In the form shown, the particle is made of gold, silver, or
manganese dioxide.
[0016] In the form shown, the graphene sheet is made by chemical
vapor deposition and wet transfer, the semiconductor substrate is
made of titanium dioxide, the graphene sheet is formed of three
graphene layers, and the particle is made of gold.
[0017] The present invention further provides a semiconductor
structure including a semiconductor substrate, a graphene sheet,
and a particle. The graphene sheet has a first surface and a second
surface opposite to the first surface. The first surface of the
graphene sheet is adhered to the semiconductor substrate. The
particle is deposited on the second surface of the graphene sheet.
The semiconductor substrate is made by the method for
photodepositing the particle on the graphene-semiconductor hybrid
panel of the present invention.
[0018] In the method for photodepositing the particle on the
graphene-semiconductor hybrid panel, the semiconductor substrate is
irradiated by the light source for generating the photoinduced
electron and hole, and then the electron and hole are transferred
to the graphene sheet. The precursor is reduced or oxidized by the
electron or the hole to form the particle directly deposited on the
surface of the graphene sheet. Thus, the function of directly
depositing the particle on the surface of the graphene is
achieved.
[0019] By using the method for photodepositing the particle on the
graphene-semiconductor hybrid panel in the present invention, the
particle is deposited on the surface of the graphene sheet by
irradiation using the light source. Thus, the process of depositing
the particle on the graphene sheet is simplified without the need
of modifying the graphene.
[0020] Furthermore, according to the method for photodepositing the
particle on the graphene-semiconductor hybrid panel in the present
invention, the precursor is reduced or oxidized by the electron or
hole generated in the semiconductor substrate and transferred by
the graphene sheet. As such, the particle is deposited directly on
the charge transfer site of the graphene sheet, thus providing an
excellent charge transfer efficiency of the particle.
[0021] In addition, according to the method for photodepositing the
particle on the graphene-semiconductor hybrid panel in the present
invention, since the particle is deposited on the
graphene-semiconductor hybrid panel by irradiation using the light
source, the light source may be controlled to irradiate only a
specific area to deposit the particle in the specific area. The
method for photodepositing the particle on the
graphene-semiconductor hybrid panel of the present invention is
also capable of depositing the particle on a large-sized graphene
sheet.
[0022] With accordance to the semiconductor structure in the
present invention, since the particle is directly deposited on the
surface of the graphene sheet, the charges may directly be
transferred between the graphene sheet and the particle without
flowing through the functional group, which is necessary in the
conventional method. Thus, the electrochemical activity of the
particle is improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will become more fully understood from
the detailed description given hereinafter and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0024] FIG. 1 illustrates a fabricating procedure of a
graphene-semiconductor hybrid panel according to the present
invention.
[0025] FIG. 2 illustrates a mechanism of a method for
photodepositing a particle on a graphene-semiconductor hybrid panel
according to the present invention.
[0026] FIG. 3 is a SEM image of the experimental result of Group
A1.
[0027] FIG. 4 is a SEM image of the experimental result of Group
A2.
[0028] FIG. 5 is a SEM image of the experimental result of Group
A3.
[0029] FIG. 6 is a SEM image of the experimental result of Group
A4.
[0030] FIG. 7 is a SEM image of the experimental result of Group
C.
[0031] FIG. 8 is a SEM image of the experimental result of Group
D.
[0032] FIG. 9 shows the SERS results of Group D0-D3.
[0033] FIG. 10 shows the enhancement factors of Group D0-D3.
[0034] In the various figures of the drawings, the same numerals
designate the same or similar parts. Furthermore, when the terms
"first", "second", "third", "fourth", "inner", "outer", "top",
"bottom", "front", "rear" and similar terms are used hereinafter,
it should be understood that these terms have reference only to the
structure shown in the drawings as it would appear to a person
viewing the drawings, and are utilized only to facilitate
describing the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0035] A method for photodepositing a particle on a
graphene-semiconductor hybrid panel according to the present
invention includes providing a graphene-semiconductor hybrid panel
having a semiconductor substrate and a graphene sheet, dipping the
graphene-semiconductor hybrid panel in a fluid, and irradiating the
graphene-semiconductor hybrid panel for photodepositing a particle
on a surface of the graphene sheet. Thus, the particle can be
deposited on the surface of the graphene sheet without the need of
modifying the graphene.
[0036] In more detail, the graphene sheet is adhered to a surface
of the semiconductor substrate, thus forming the
graphene-semiconductor hybrid panel. The semiconductor substrate
may be, but not limited to, silicon dioxide (SiO.sub.2), silicon
nitride (Si.sub.3N.sub.4), aluminum oxide (Al.sub.2O.sub.3),
titanium dioxide (TiO.sub.2), tantalum (III) oxide
(Ta.sub.2O.sub.3), zinc oxide (ZnO), hafnium (IV) oxide
(HfO.sub.2), zirconium dioxide (ZrO.sub.2), lanthanum oxide
(La.sub.2O.sub.3), yttrium (III) oxide (Y.sub.2O.sub.3), cadmium
oxide (Cd.sub.2O.sub.3), erbium oxide (Er.sub.2O.sub.3), neodymium
(III) oxide (Nd.sub.2O.sub.3), praseodymium (IV) oxide (PrO.sub.2),
cerium (IV) oxide (CeO.sub.2), gallium nitride (GaN), gallium
arsenide (GaAs), zinc sulfide (ZnS), indium nitride (InN). The
graphene sheet may be produced by chemical vapor deposition,
mechanical exfoliation, chemical exfoliation, or epitaxial growth,
and may be formed of a single graphene layer as well as a plurality
of graphene layers stacked together. It is noted that the graphene
sheet in the present invention can be made by any process, and the
thickness, homogeneity, and number of layers of the graphene sheet
are not limited. In this embodiment, a graphene layer is initially
chemical vapor deposited, and than being wet transferred to the
semiconductor substrate. The graphene layer produced by chemical
vapor deposition can advantageously have a uniform thickness and
homogeneity. In addition, the graphene sheet formed of a plurality
graphene layers can be easily produced by repeating the wet
transfer step. The thickness of the single graphene layer may be of
0.6-1.5 nm, and preferably of 0.8-0.9 nm.
[0037] Specifically, the graphene layer in this embodiment may be
produced on a copper foil by chemical vapor deposition under a low
pressure condition. The copper foil is placed in a quartz tube at
10.sup.-3 Torr, then, the chemical vapor deposition system is
heated up to 1000.degree. C. with a flow of hydrogen gas at 10 sccm
for 20 minutes for cleaning and annealing the surface of the copper
foil. Next, the atmosphere inside the chemical vapor deposition
system is changed to a mixture of CH.sub.4 at 10 sccm and H.sub.2
at 35 sccm for 40 minutes. Finally, the chemical vapor deposition
system is cooled to room temperature under argon flow at 60 sccm.
The graphene layer produced on the copper foil is coated by a thin
layer of poly(methyl methacrylate) (PMMA) before the copper foil is
etched away with an ammonium persulfate aqueous solution. The
graphene layer coated by the thin layer of PMMA is then transferred
to the surface of the semiconductor substrate, followed by removing
the thin layer of PMMA using an organic solvent, such as toluene.
Thus, the graphene layer is produced and adhered to the surface of
the semiconductor substrate, and the graphene-semiconductor hybrid
panel is obtained. Please refer to FIG. 1, after a first graphene
layer "G1" has been adhered to the semiconductor substrate "S,"
another graphene layer "G2" coated by the thin layer of PMMA can be
wet transferred to a surface of the graphene layer "G1," and the
thin layer of PMMA may be removed to form a second graphene layer
"G2" on the graphene-semiconductor hybrid panel. By repeating the
above steps, the graphene-semiconductor hybrid panel may be
produced with the graphene sheet "G" formed of a plurality of
graphene layers, such as the graphene layer marked "G1," "G2" and
"G3" shown in FIG. 1.
[0038] The fluid includes a precursor of the particle. The
precursor contains a cation, an anion, or a molecule, which can be
reduced or oxidized by an electron or a hole to form the particle.
In addition, the precursor may contain two or more kinds of ions
and/or molecules for the purpose of depositing different particles
at the same time. Specifically, the particle may be made of metal
or alloy, such as gold, silver, copper, iron, cadmium, zinc,
cobalt, nickel, chromium, aluminum, magnesium, gold-silver alloy,
silver-copper alloy. Moreover, the particle may be made of metal
oxide, such as manganese dioxide, cobalt oxide, iron oxide, silicon
dioxide, copper oxide, zinc oxide, magnesium oxide, and zirconium
dioxide.
[0039] However, this is not to be taken as a limited sense. The
precursor is selected corresponding to the elemental composition of
the particle. For example, the precursor may be a metal ion, which
can be reduced to form the particle of metal, as it would be
understood by the persons ordinarily skilled in the art. The fluid
may be a solvent or a gel for dissolving the precursor without
damaging the semiconductor substrate.
[0040] The light source refers to any radiation form with energy
for exciting the electrons or holes in the semiconductor substrate.
Specifically, the light source may have an energy equal to or
higher than the band gap of the semiconductor. For example, the
light source may be UV light with a wavelength of 365 nm for the
semiconductor made of titanium oxide or zinc oxide. Furthermore, a
user can control the light source to irradiate only a specific area
on the graphene-semiconductor hybrid panel for photodepositing the
particle inside the specific area. Please refer to FIG. 2, which
shows the mechanism of the method for photodepositing the particle
on the graphene-semiconductor hybrid panel. The
graphene-semiconductor hybrid panel is dipped in the fluid and
surrounded by the precursor "I". Next, the graphene-semiconductor
hybrid panel is irradiated and excited by the light source "L",
thus generating the photoinduced electrons and holes in the
semiconductor substrate "S." The electrons or holes then transfer
to the graphene sheet "G" and reduce or oxidize the precursor "I"
to form the particle "M" deposited on the surface of the graphene
"G" Since the precursor can only be reduced or oxidized at a site
capable of charge transferring, the particle is therefore precisely
deposited on a charge transfer site of the graphene, which results
in an excellent charge transfer efficiency. Moreover, by
controlling the size of the graphene sheet and the irradiating area
of the light source, the method for photodepositing the particle on
the graphene-semiconductor hybrid panel may be easily applied to a
large-sized graphene-semiconductor hybrid panel.
[0041] As such, the method for photodepositing the particle on the
graphene-semiconductor hybrid panel of the present invention can
directly deposit the particle on the surface of the graphene sheet
without the need of modifying the graphene sheet.
[0042] The present invention further provides a semiconductor
structure including a semiconductor substrate, a graphene sheet and
a particle. The graphene sheet has a first surface and a second
surface opposite to the first surface. The first surface of the
graphene sheet is adhered to the semiconductor substrate, and the
particle is deposited on the second surface of the graphene sheet.
The semiconductor structure is produced by the method for
photodepositing the particle on the graphene-semiconductor hybrid
panel as described in the above. As such, the particle is precisely
deposited on the charge transfer site, thus providing excellent
charge transfer efficiency and photochemical activity of the
semiconductor structure. Therefore, the semiconductor may be
applied in the electrochemical field. For example, the
semiconductor structure in the present invention is capable of
biomedical detection, multi-component mixed catalysis, solar cell,
flexible flat panel display, touch panel, semiconductor element
coating layer, thermal conductive pad, high-performance display,
transparent conductive thin film, ambient light sensor, fuel cell,
lithium cell, high-performance transistor, water or pollution
filtration, wireless communication, and high-speed transistor.
[0043] The particle is selected corresponding to the application of
the semiconductor. For example, the particle may be made of an
organic material for photocatalysis or solar cell. On the other
hand, the semiconductor structure with the particle made of metal
or metal oxide, such as gold or silver, may have an excellent
surface-enhanced Raman scattering (SERS) efficiency for an SERS
substrate of detecting biomedical targets such as DNA and
virus.
[0044] For validating the function of the method for directly
depositing the particle on the surface of the
graphene-semiconductor hybrid panel, several experiments are
carried out as follows.
[0045] In Group A1, A2, and A3 of the first experiment, the
graphene-semiconductor hybrid panels with single-layer, 3-layer and
7-layer graphene sheet are produced using chemical vapor deposition
and wet transfer method as described in the above with the
semiconductor substrate being titanium oxide. Another
graphene-semiconductor hybrid panel having 3-layer graphene sheet
is produced and treated with oxygen plasma for 5 seconds with a
power of 10 W under a low-pressure oxygen atmosphere
(2.1.times.10.sup.-1 Torr) as the graphene-semiconductor hybrid
panel of Group A4.
[0046] An ethanol solution of 0.001 M chloroauric acid is used as
the fluid, which contains a gold ion as the precursor. The
graphene-semiconductor hybrid panels of Group A1-A4 are
individually placed in quartz tubes, and the fluid is respectively
added in every quartz tube. Next, these graphene-semiconductor
hybrid panels are irradiated by the light source to photodeposit
the gold particle on the surface of the graphene sheet. The light
source used in this experiment is a UV light of 365 nm and 16
W.
[0047] Please refer to FIGS. 3-6, which are the SEM images of the
graphene-semiconductor hybrid panels of Group A1-A4. For Group
A1-A3. As can be seen in the figures, the particles are deposited
on the surface of the graphene sheet with uniform distribution. By
using the graphene sheets with different numbers of graphene
layers, the amount, sizes and distributing density of the particles
may be regulated. It is noted that the graphene-semiconductor
hybrid panel with 3 graphene layers (Group A2, as shown in FIG. 4)
has the sizes and distribution of the gold particle being most
uniform over Group A1-A3. Referring to the graphene-semiconductor
hybrid panel of Group A4 as shown in FIG. 6, it is noted that the
particle can also be deposited on the graphene sheet with its
surface being modified by oxygen plasma. That is, the method for
photodepositing the particle on the graphene-semiconductor hybrid
panel in the present invention can be achieved with the
graphene-semiconductor hybrid panel having pristine or modified
graphene sheet.
[0048] In another experiment, the graphene-semiconductor hybrid
panel with single graphene layer is prepared as the
graphene-semiconductor hybrid panel of Group B and C. In Group B,
the particle made of silver is deposited using an ethanol solution
of 0.001 M silver nitrate and a UV light of 365 nm In Group C, the
particle made of manganese dioxide is deposited using an aqueous
solution of 0.001 M potassium permanganate (VII) and a UV light of
365 nm.
[0049] The SEM images of the graphene-semiconductor hybrid panel of
Group B and C are respectively shown as FIGS. 7 and 8. Accordingly,
the method for photodepositing the particle on the
graphene-semiconductor hybrid panel is capable of depositing the
particle of silver or manganese dioxide. As a summary of the above,
the method for photodepositing the particle on the
graphene-semiconductor hybrid panel may actually deposit the
particle made of various materials on the surface of both pristine
and modified graphene sheets with uniform distribution of the
particle.
[0050] Another set of experiments is carried out for validating the
semiconductor structure in the present invention, where the
particle is deposited on the charge transfer site, thus forming the
semiconductor structure with excellent electrochemical
activity.
[0051] In the Group D0, a gold-deposited semiconductor substrate is
produced by photodepositing the gold particle on a surface of the
semiconductor substrate without graphene sheet. The gold-deposited
graphene-semiconductor hybrid panels of previous Group A1-A3 are
taken as the semiconductor structures of Group D1-D3. Another
semiconductor substrate without graphene sheet is taken as the
control group (Group R).
[0052] An ethanol solution of 10.sup.-5 M R6G (rhodamine 6G) is
prepared as a sample solution, and another ethanol solution of
10.sup.-3 M R6G is prepared as a reference solution. A droplet of
the sample solution is dropped on each of the gold-deposited
semiconductor substrate and the semiconductor structures in Groups
D0-D3, and a droplet of the reference solution is dropped on the
semiconductor substrate of Group R. All of them are dried under
ambient conditions. The Raman signal of R6G in Groups R and D0-D3
are acquired under a 633 nm He-Ne laser with a power of 2 mW.
[0053] Please refer to FIG. 9, which shows the Raman signal results
of Group D0-D3. The peaks labeled with the asterisk sign in the
figure correspond to the vibration mode of R6G. Since the particle
(which is made of gold in this experiment) is directly deposited on
the surface of the graphene sheet, the charges may flow fluently
through the semiconductor substrate, the graphene sheet and the
particle. Thus, an excellent efficacy of surface plasmon resonance
is provided by the graphene sheet and the particle.
[0054] Please refer to FIG. 10, which shows the enhancement factor
(EF) of Group D0-D3. The enhancement factor of SERS is defined as
EF=(I.sub.SERS/I.sub.R)/(N.sub.R/N.sub.SERS), where I.sub.SERS and
I.sub.R are the integrated intensity of the R6G peak at 1510
cm.sup.-1 collected respectively of Group D0-D3 and Group R, and
N.sub.SERS and N.sub.R are the numbers of molecules of Group D0-D3
and Group R respectively. According to this figure, the
enhancements of Group D1-D3 are significantly higher than that of
Group D0. The enhancement factor of Group D2 is about 10.sup.8,
which is the largest one among all.
[0055] With reference to FIGS. 9 and 10, the function of the
semiconductor structure of the present invention is confirmed.
Since the particle is directly deposited on the graphene sheet, the
charges are capable of flowing through the graphene sheet, the
semiconductor substrate and the particle. Thus, the electrochemical
activity of the particle is improved. The semiconductor structure
may have an excellent SERS enhancement when the particle is made of
gold, and may be used as the SERS substrate.
[0056] In conclusion, in the method for photodepositing the
particle on the graphene-semiconductor hybrid panel, the
semiconductor substrate is irradiated by the light source for
generating the photoinduced electron and hole, and then the
electron and hole are transferred to the graphene sheet. The
precursor is reduced or oxidized by the electron or the hole to
form the particle directly deposited on the surface of the graphene
sheet. Thus, the function of directly depositing the particle on
the surface of the graphene is achieved.
[0057] By using the method for photodepositing the particle on the
graphene-semiconductor hybrid panel in the present invention, the
particle is deposited on the surface of the graphene sheet by
irradiation using the light source. Thus, the process of depositing
the particle on the graphene sheet is simplified without the need
of modifying the graphene.
[0058] Furthermore, according to the method for photodepositing the
particle on the graphene-semiconductor hybrid panel in the present
invention, the precursor is reduced or oxidized by the electron or
hole generated in the semiconductor substrate and transferred by
the graphene sheet. As such, the particle is deposited directly on
the charge transfer site of the graphene sheet, thus providing an
excellent charge transfer efficiency of the particle.
[0059] In addition, according to the method for photodepositing the
particle on the graphene-semiconductor hybrid panel in the present
invention, since the particle is deposited on the
graphene-semiconductor hybrid panel by irradiation using the light
source, the light source may be controlled to irradiate only a
specific area to deposit the particle in the specific area. The
method for photodepositing the particle on the
graphene-semiconductor hybrid panel of the present invention is
also capable of depositing the particle on a large-sized graphene
sheet.
[0060] With accordance to the semiconductor structure in the
present invention, since the particle is directly deposited on the
surface of the graphene sheet, the charges may directly be
transferred between the graphene sheet and the particle without
flowing through the functional group, which is necessary in the
conventional method. Thus, the electrochemical activity of the
particle is improved.
[0061] Although the invention has been described in detail with
reference to its presently preferable embodiments, it will be
understood by one of ordinary skill in the art that various
modifications can be made without departing from the spirit and the
scope of the invention, as set forth in the appended claims.
* * * * *