JPS63201659A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance transferability of carrier and to obtain high resistance and superior triboelectrification characteristics by alternately laminating thin layers different in optical band gap from each other to use a superlattice structure for a photoconductive layer. CONSTITUTION:A electrophotographic sensitive body is obtained by successively laminating on a conductive substrate 1 a blocking layer 2, the photoconductive layer 3 composed of an electric charge holding layer 5 and a charge generating layer 6, and on this layer 6 a surface layer 4. Each of the layers 5, 6 has superlattice structure, and the layer 5 is formed by alternately laminating thin films of amorphous silicon and thin films of amorphous silicon containing at least one of C, O, and N, the layer 6 is constituted by alternately laminating thin films of amorphous silicon and thin films of microcrystalline silicon, and the crystallization degree of the microcrystalline silicon is changed in the film thickness direction in each thin film, thus permitting the obtained electrophotographic sensitive body to be superior in chargeability, low in residual potential, high in sensitivity to lights in the wide wavelength region to the near infrared region, good in adhesion to the substrate 1, and excellent in resistance to environmental conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor having excellent charging characteristics, dark decay characteristics, photosensitivity characteristics, environmental resistance, etc.

[Prior art] Amorphous silicon (hereinafter referred to as a) containing hydrogen (H)
-81:H) has recently attracted attention as a photoelectric conversion material, and has been applied to photoreceptors in electrophotographic processes as well as solar cells, thin film transistors, and image sensors.

Conventionally, CdS r ZnO, Be + or S@-TlB has been used as a material constituting the photoconductive layer of an electrophotographic photoreceptor.
or poly-IJ-N-vinylcarbazole (
PVCz ) or trinitrofluorenone (TNF
) and other organic materials were used. However, h-
Compared to these inorganic or organic materials, at:H is a non-polluting substance and does not require recovery treatment, has high spectral sensitivity in the visible light region, and has high surface hardness and wear resistance. It has advantages such as excellent impact resistance. For this reason, a-81:H is attracting attention as a photoreceptor material for electrophotographic processes.

This a-8i:'H is being studied as a photoreceptor material based on the Karun system, but in this case, the photoreceptor is required to have high resistance and photosensitivity. However, it is difficult to satisfy both of these characteristics with a single photoreceptor, so a barrier layer is provided between the photoconductive layer and the conductive support, and a surface charge retention layer is provided on the photoconductive layer. These requirements are satisfied by providing a laminated structure.

[Problems to be Solved by the Invention] By the way, a-8l:H is usually formed by a glow discharge decomposition method using a silane-based gas, but at this time *
a-8t: Hydrogen is taken into the H film, and the electrical and optical characteristics vary considerably due to the difference in the amount of hydrogen. That is, when the amount of hydrogen entering the a-81:H film increases,
The optical bandgap becomes larger and the resistance of a-8i:H becomes higher, but as a result, the photosensitivity to long wavelength light decreases, so it is not suitable for use in, for example, a Radhebeam printer equipped with a semiconductor laser. It is difficult to do so.

Also, when the hydrogen content in the a-8S:H film increases,
Depending on the film forming conditions, materials having bonding structures such as (SiH2)n and SiH2 may occupy most of the area in the film. Then? The photoconductive properties deteriorate due to the increase in id and the increase in silicon dangling bonds.
It becomes unusable as an electrophotographic photoreceptor. On the contrary, h-8t
As the amount of hydrogen incorporated into :H decreases, the optical bandgap decreases and its resistance decreases, but the photosensitivity to long wavelength light increases. However, when the hydrogen content is low, there is less hydrogen to combine with and reduce the dangling bonds of silicon. For this reason, the mobility of the generated carriers is reduced, the life span is shortened, and the photoconductive properties are deteriorated, making it difficult to use as an electrophotographic photoreceptor.

In this way, the photoconductive layer of the electrophotographic photoreceptor can be formed into a single a-8
If it is composed of only the i:H layer, there is a problem that the characteristics change greatly depending on the manufacturing conditions of the a-81:H layer, and desired characteristics cannot be obtained.

The present invention has been made in view of such circumstances, and
To provide an electrophotographic photoreceptor that has excellent charging ability, low residual potential, high photosensitivity over a wide wavelength range up to the near infrared region, good adhesion to a substrate, and excellent environmental resistance. The purpose is

[Structure of the Invention] (Means for Solving the Problems) As a result of various studies, the present inventors have constructed a photoconductive layer of an electrophotographic photoreceptor including a charge retention layer and a charge generation layer,
The present inventors have discovered that the above object can be achieved by stacking a plurality of predetermined semiconductor films, that is, forming a region with a superlattice structure, and have completed the present invention.

That is, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor comprising an electrically conductive support and a photoconductive layer, the photoconductive layer comprising a charge generation layer and a charge retention layer, The holding layer is constituted by alternately laminating amorphous silicon thin films and amorphous silicon thin films containing at least one element selected from carbon, oxygen, and nitrogen, and the charge generation layer is made of amorphous silicon thin films. It is constructed by alternately laminating thin films and microcrystalline silicon thin films, and is characterized in that the crystallinity of the microcrystalline silicon thin films varies from film to film in the layer thickness direction.

The microcrystalline silicon (μc-81) used in the present invention is thought to be formed of a mixed layer of microcrystalline silicon and amorphous silicon with a grain size of about several tens of Angstroms, and is as follows: It has the following physical properties.

First, X-ray diffraction measurements show a crystal diffraction pattern with 2θ in the vicinity of 28 to 28.5 degrees, which can be adjusted to more than 20 degrees, and is clearly visible even from polycrystalline silicon with a dark resistance of 100. distinguished.

The optical bandgap (Ego) of μe -81 used in the present invention is desirably 1.55 eV, for example. However, it can be set arbitrarily within a certain range. Preferably, the required amount of hydrogen is added to each to obtain the desired Eg 2 O and used as μc-8l:H.

This compensates for silicon dangling, balances dark resistance and bright resistance, and improves photoconductive properties.

Note that actual μc-St films often have weak P-type or N-type characteristics depending on specific factors such as manufacturing conditions (
(Especially likely to become type N). Therefore, in order to obtain the type 1 required for forming a superlattice structure, it is desirable to lightly dope impurities having opposite conductivity types to cancel out the P type or N type.

The crystallinity of the microcrystalline silicon thin film constituting the charge generation layer is preferably 60 to 90%, more preferably 60 to 5O.
It is preferable to change it within the range of qb.

(Function) In the electrophotographic photoreceptor of the present invention, the carriers generated have a long life and a high mobility in the rounded region in which the photoconductive layer is provided with the superlattice structure. Although the theory is not fully established yet, is it a periodic well type characteristic of superlattice structures? There is no doubt that this is a quantum effect due to the tensile, and this is especially called the superlattice effect.

In this way, carrier mobility in the photoconductive layer increases,
Furthermore, the sensitivity of the electrophotographic photoreceptor is significantly improved due to the longer life of the carrier.

(Example) FIG. 1 is a diagram showing a cross-sectional structure of an electrophotographic photoreceptor according to an example of the present invention. In the figure, conductive support 1
A top barrier layer 2 is formed thereon, and a photoconductive layer 3 consisting of a charge retention layer 5 and a charge generation layer 6 is formed thereon.

Further, a surface layer 4 is formed on the charge generation layer 6.

Note that both the charge retention layer 5 and the charge generation layer 6 have a superlattice structure.

Hereinafter, the structure of the electrophotographic photoreceptor shown in FIG. 1 will be explained in more detail.

The conductive support 1 usually consists of a drum made of aluminum.

The barrier layer 2 may be formed using .mu.c-81'p m-81:H, or a-BN:H (amorphous boron to which nitrogen and hydrogen are added).

Furthermore, an insulating film may be used. For example, μc −8
By incorporating one or more elements selected from carbon C1 nitrogen N and oxygen O into i:H and a-81:H, a high-resistance insulating barrier layer can be formed. The thickness of the barrier layer 2 is preferably 100X to 10 μm.

The barrier layer 2 is formed in order to suppress the flow of charges between the conductive support 1 and the charge generation layer 5, thereby increasing the charge retention function of the surface of the photoreceptor and increasing the charging ability of the photoreceptor. It is something. Therefore, when using the semiconductor layer as a tube barrier layer to construct a Carlson type photoreceptor, the barrier layer 2 is made to be P type or N type in order not to reduce the ability to retain the electric charge charged on the surface. That is, when the surface of the photoreceptor is positively charged, the barrier layer 2 is made of P type to prevent electrons that neutralize the surface charge from being injected into the charge generation layer.

Conversely, when the surface is negatively charged, the barrier layer 2 is made of N type,
This prevents holes that neutralize surface charges from being injected into the charge generation layer. Since carriers injected from the barrier layer 2 become noise with respect to carriers generated in the charge generation layer 6 upon incidence of light, preventing carrier injection as described above improves sensitivity. In addition, μc-81:H
or a-8t: In order to make the Hl-P type, elements belonging to Group Ⅰ of the periodic table, such as boron B, aluminum At,
Gallium G&% Indium I n s and Thallium T
It is preferable to dope with t or the like. Maroku, μc-8
To make i:H or a-8t:Hl-N type, elements belonging to Group V of the periodic table, such as nitrogen, phosphorus P1 arsenic A1%
It is preferable to dope with antimony Sb, bismuth Bi, or the like.

The charge generation layer 6 generates carriers when light is incident thereon, and carriers of one polarity neutralize the charges on the surface of the photoreceptor, and the other carriers travel within the charge retention layer 5 and become conductive. The sexual support 1 is reached.

The charge retention layer 5 and the charge generation layer 6 are each constructed by alternately laminating two types of thin layers.

These thin layers have different optical bandgaps and each have a thickness in the range of 30-200X. In this way, by laminating thin layers with mutually different optical bandgaps, a layer with a large optical bandgap can be created based on a layer with a small optical bandgap, regardless of the size of the optical bandgap itself. A superlattice structure having periodic potential barriers is formed. In this superlattice structure, the barrier thin layer is extremely thin, so
Due to carrier tunneling in the thin layer, carriers pass through the barrier and travel into the superlattice structure. Furthermore, in such a superlattice structure, a large number of carriers are generated due to the incidence of light. Therefore, it has high photosensitivity. In addition,
By changing the bandgap and layer thickness of the thin layer of the superlattice structure, the apparent bandgap of the layer having the heterojunction superlattice structure can be freely adjusted.

A-81 constituting the charge retention layer 5 and the charge generation layer 6:
The hydrogen content in H and μc-81:H is 0.
01 to 30 atoms are preferred, and 1 to 25 atoms are more preferred. This hydrogen content compensates for the dangling effect of silicon, harmonizes the dark resistance and bright resistance, and improves the photoconductive properties.

*-81: To form an H layer by the glow discharge decomposition method, silane gases such as SiH4 and Si2H are introduced into the reaction chamber as raw materials, and the H layer is formed into a thin layer by eliglow discharge at high frequency. H can be added. If necessary, hydrogen or helium gas can be used as a carrier for the silanes. On the other hand, % SiF4 is 51ct4f! Silicon halides such as gas can be used as the raw material gas.

In addition, even if the reaction is performed with a mixed gas of silane gas and silicon halide gas, a-8t:Hf containing H
t film can be formed. Note that these thin layers can be formed not by the glow discharge decomposition method but also by a physical method such as sputtering.

Like a-81:H, the Ac-81 layer can also be formed using silane gas as a raw material by the high-frequency glow discharge decomposition method. In this case, the temperature of the support is a-8i:
The high frequency power is set higher than when forming H, and the high frequency power is also a-
If it is set higher than the case of 8t:H, μe-81:H
becomes easier to form. Furthermore, by increasing the support temperature and high-frequency power, the flow rate of raw material gases such as silane gas and the like can be increased, and as a result, the film formation rate can be increased. In addition, SiH4 and S of the raw material gas
By using a higher order silane gas such as i 2 H6 diluted with hydrogen, μc-8l:H can be formed with even higher efficiency.

To make μc-81:H and a-81:H P-type, elements belonging to Group Ⅰ of the periodic table, such as boron B, aluminum At, gallium Gas, Innoum Ins, and thallium Tt, are added. It is preferable to dope, and in order to make μc-St:H and a-8i:H n-type, elements belonging to Group V of the periodic table, such as nitrogen N1 phosphorus P, arsenic A s % antimony Sb .

It is preferable to dope with bismuth Bi or the like.

This doping with p-type impurities or n-type impurities prevents charges from moving from the support side to the photoconductive layer. On the other hand, in μc-8t:H and a-8i:H, carbon C1
By incorporating at least one element selected from nitrogen (N) and oxygen (O), high resistance can be achieved and the surface charge retention ability can be increased. The content of these elements is 5
~40 atoms, preferably 10 to 30 atoms.

A surface layer 4 is provided on the charge generation layer 6.

Since a-8i:H and the like of the charge generation layer 6 has a relatively large refractive index of 3 to 3.4, light reflection easily occurs on the surface. When such light reflection occurs, the proportion of the amount of light absorbed by the photoconductive layer or the charge generation layer decreases, resulting in increased light loss. For this reason, it is preferable to provide the surface layer 4 to prevent reflection. Further, by providing the surface layer 4, the charge generation layer 6 is protected from damage. Furthermore, by forming the surface layer, the charging ability is improved, and the charge can be easily deposited on the surface. The material forming the surface layer is a-
8IN: Hla-810: Hl and a-SIC: H
and organic materials such as polyvinyl chloride and polyamide.

When the bottom surface of the electrophotographic photoreceptor constructed in this manner is charged with a positive voltage of approximately 500 V by corona discharge, a potential barrier is formed. When light (hv) is incident on this photoreceptor, carriers of electrons and holes are generated in the superlattice structure of the charge generation layer 6. Electrons in the conduction band are accelerated toward the surface layer 4 side by the electric field in the photoreceptor, and holes are accelerated toward the conductive support J side. In this case, the number of carriers generated at the boundary between thin layers with different optical band gaps is much larger than the number of carriers generated in the bulk. Therefore, this superlattice structure has high photosensitivity. In addition, in the potential well layer, due to quantum effects, compared to the case of a single layer without a superlattice structure,
Carrier life is 5 to 10 times longer. Furthermore, in a superlattice structure, a periodic barrier layer is formed due to bandgap discontinuity, or carriers easily pass through a bias layer due to tunneling, so the effective carrier mobility is similar to the bulk mobility. The carrier has excellent runnability.

Similarly, in the case of the charge retention layer 6, the lifetime of carriers in the potential well layer is 5 to 10 times longer than in the case of a single layer without a superlattice structure due to quantum effects.

In addition, in a superlattice structure, a periodic barrier layer is formed due to discontinuity in the band gap, but carriers easily pass through the bias layer due to the tunnel effect.
The effective mobility of the carrier is equivalent to the mobility in bulk, and the carrier has excellent mobility. As mentioned above,
A super high polymer structure in which thin layers having different optical band gaps are laminated can provide high photoconductivity, and even a conventional photoreceptor can produce clear images.

Referring to FIG. 2, an apparatus and a manufacturing method for manufacturing the electrophotographic photoreceptor of the above embodiment by a glow discharge method will be described below. Same figure Kj? Is there a problem? Empe21,22e23
*24 includes, for example, SiH4°B2H6, H2, C
A raw material gas such as H4 is contained.

The gas in these gases is supplied to a mixer 28 via a pulp 26 for flow filling and piping 27. A pressure gauge 25 is installed in each pressure gauge, and by adjusting the pulp 26 while monitoring the pressure gauge 25, the flow rate and mixing ratio of each raw material gas supplied to the mixer 28 can be adjusted.

The gas mixed in the mixer 28 is supplied to a reaction vessel 29. A rotating shaft 30 is attached to the bottom 31 of the reaction vessel 29 so as to be rotatable around the vertical direction. The rotating shaft 3
At the upper end of 0, a disk-shaped support 32 has its surface aligned with the rotation axis 30.
It is fixed vertically. Inside the reaction vessel 29, a cylindrical electrode 33 is installed on the bottom 31 with its axial center aligned with the axial center of the rotating shaft 30. A drum base 34 of a photoreceptor is placed on a support base 32 with its axial center aligned with the axial center of the rotating shaft 30.
A heater 35 for heating the drum base is disposed inside the drum. A high frequency power source 36 is connected between the electrode 33 and the drum base 34, and the electrode 33 is connected to the drum base 34.
It is a trap where a high frequency current is supplied between them. The rotating shaft 30 is rotationally driven by a motor 3BVC. Reaction container 2
The pressure inside the reaction vessel 29 is monitored by a pressure gauge 37.
is connected to a suitable evacuation means such as a vacuum pump via an r-pulp 38.

When manufacturing a photoreceptor using the above-mentioned manufacturing apparatus, after the drum base 34 is installed in the reaction container 29.

Open the dart valve 39 and let the inside of the reaction vessel 29 cool to about 0.1
Evacuate to pressure below Torr. Next, Dembe 21
．． 21! , 23 and 24, the required reaction gases are mixed at a predetermined mixing ratio and introduced into the reaction vessel 29.

In this case, the amount of light introduced into the reaction container 29 is set so that the pressure inside the reaction container 29 is 0.1 to 1.0 TorrK.Next, the motor 38 is operated to rotate the drum base 34, Heater 35 and drum base 34
is heated to a constant temperature, and a high frequency current is supplied between the electrode 33 and the drum base 34 by the high frequency power supply 36 to form a glow discharge between them. On top of this, 1ca-8t:H is deposited on the drum base 34. In addition, in the raw material, N20, NH,, NO□e N2 e CH
4# There is no need to use C2H4e O□ gas, etc.
Carbon, oxygen, and nitrogen can be included in a-81:H.

As described above, the electrophotographic photoreceptor according to the present invention can be manufactured using a closed system manufacturing apparatus, and therefore is safe for the human body.

Next, the results of testing the electrophotographic properties of an electrophotographic photoreceptor according to the present invention formed into a film will be described.

Test Example 1 If necessary, to prevent interference, an aluminum drum base with a diameter of 80 mm and a width of 350 mm, which has been subjected to acid treatment, alkali treatment, and sandblasting, is installed in the reaction vessel. The vacuum was evacuated to approximately 10-5 torr.

The drum base was heated to 250°C, and while rotating at 10 rpm, 500 SCCM of 5tH4 gas was added to B2H.
6. Gas was introduced into the reaction vessel at a flow rate ratio of 1O-3 to 5IH4 gas, and the pressure inside the reaction vessel was reduced to l T
Adjusted to orr. Then, high frequency power of 13.56 MHz was applied to generate plasma to form a p-type a-SiC:H barrier layer on the drum substrate.

Next, SiH4 gas was introduced into the reaction vessel at a flow rate of 500 SCCM, CH4, f gas was introduced into the reaction vessel at a flow rate of 30 SCCM,
0W high frequency power tube applied, 120X a-81C:
A thin H layer was formed. Next, CH4 gas was set to 0, and B
2H6 gas was introduced into the reaction vessel at a flow rate ratio of 10 to SiH4, and 400 W of high frequency power was similarly applied to form a 1201C)i type a-81:H thin layer. Repeat this operation to create 500 layers of A-8.
A charge retention layer having a superlattice structure of 12 μm consisting of an iC:H thin layer and 500 1-81:H thin layers was formed.

Then the 5in4 is 50 SCCM, N2. f gas was introduced at a flow rate of 500 SeCM, the pressure inside the reaction vessel was set to ITorr, and a high frequency power of 1.2 kW was applied to form a 100^ μc-8i:H thin layer. The crystallinity of this thin layer was 80%. Next, 5IH4 gas was introduced into the reaction vessel at a flow rate of 500SCCM, such that the flow rate ratio to B2H6t S IH4 gas was 10, and 500W of high frequency power was applied to 1-8 of 50X.
One thin layer was formed. These operations were repeated to form a charge generation layer having a superlattice structure of 3 μm. However, μc −
When forming the 8l2H thin layer, the high frequency power was gradually lowered as each thin layer was formed, finally reaching 700 W, and the degree of crystallinity was varied from 80% to 60%.

Finally, a surface layer consisting of a 0.5 μm thin a-sic SH layer was formed.

When the surface of the photoreceptor thus formed is positively charged at about 500 V and exposed to white light, this light is absorbed by the charge generation layer and carriers of electron-hole pairs are generated. In this test example, a large number of carriers were generated, the carriers had a long life, and high running performance was obtained. This resulted in clear, high-quality images. In addition, when the photoreceptor manufactured in this test example was repeatedly charged, the reproducibility and stability of the transferred image were extremely good. It has been proven that the properties are excellent.

The photoreceptor manufactured in this manner has high sensitivity even to long wavelength light of 780 to 790 nm, which is the oscillation wavelength of a semiconductor radar. When this photoreceptor was installed in a semiconductor radar printer and an image was formed using the Carlson process, it was possible to obtain a clear, high-resolution image even when the exposure amount on the photoreceptor surface was 25 srgcrR''. .

Test gAI2 An electrophotographic photoreceptor was prepared in the same manner as in Test Example 1, except that an a-SIN:H thin layer was formed instead of the a-SiC:H thin layer, which is one of the constituent layers of the charge retention layer. was manufactured.

In addition, the thin layer of 凰-8IN:H is SiH4 gas t-5
The solution was achieved by introducing 00 SCCM% N2 gas into the reaction vessel at a flow rate of 808 CCM and applying 500 W of high frequency power.

When an image was formed using this photoreceptor in the same manner as in Test Example 1, a clear and high quality image was obtained.

Test Example 3 The crystallinity of the μc-81:H thin layer, which is one of the constituent layers of the charge generation layer, is shown in Figure 3 (a) e (b) e (c) =
An electrophotographic photoreceptor was produced in the same manner as in Test Example 1, except that the ratio was gradually changed as shown in (d).

When images were formed using these photoreceptors in the same manner as in Test Example 1, clear and high quality images were obtained.

Test Example 4 The crystallinity of the μc-St:H thin layer, which is one of the constituent layers of the charge generation layer, is shown in Figure 3 (1), (b), and (e).
An electrophotographic photoreceptor was produced in the same manner as in Test Example 2, except that the ratio was gradually changed as shown in (d).

When images were formed using these photoreceptors in the same manner as in Test Example 1, clear and high quality images were obtained.

The types of thin layers constituting the charge retention layer and the charge generation layer are not limited to 22ffi as in the above test example, and three or more types of thin layers may be laminated. It is sufficient to form boundaries between different thin layers.

In particular, since a superlattice structure consisting of laminated thin layers with mutually different optical band gaps is used, an electrophotographic photoreceptor with high carrier mobility, high resistance, and excellent charging characteristics can be obtained. be able to.

In particular, the present invention has the advantage that by appropriately combining materials forming the thin layer, it is possible to obtain a photoreceptor having optimal photoconductive properties for light in any wavelength band.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electrophotographic photoreceptor according to an embodiment of the present invention, FIG. 2 is a diagram showing an apparatus for manufacturing an electrophotographic photoreceptor according to an embodiment of the invention, and FIG. 3 is a thin layer of crystals. FIG. 3 is a diagram showing changes in the degree of 4...Next layer 15...Electronic-tffi layer, 6...
Charge generation layer Figure 1/I Book (a) (C) Layer 4 (b) (d '') Figure 3

Claims (9)

[Claims] (1) In an electrophotographic photoreceptor having a conductive support and a photoconductive layer, the photoconductive layer is composed of a charge generation layer and a charge retention layer, and the charge retention layer is composed of an amorphous silicon thin film and a carbon , an amorphous silicon thin film containing at least one element selected from oxygen and nitrogen are alternately laminated, and the charge generation layer is formed by alternately laminating amorphous silicon thin films and microcrystalline silicon thin films. 1. An electrophotographic photoreceptor, characterized in that the crystallinity of the microcrystalline silicon thin film varies from film to film in the layer thickness direction. (2) The electrophotographic photoreceptor according to claim 1, wherein the thin film has a thickness of 30 to 200 Å. (3) The photoconductive layer contains at least one element selected from elements belonging to Group III and Group V of the periodic table. Photographic photoreceptor. (4) The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the charge generation layer contains at least one element selected from carbon, oxygen, and nitrogen. . (5) The photoconductive layer contains at least one element selected from carbon, oxygen, and nitrogen, and the concentration thereof changes in the layer thickness direction.
The electrophotographic photoreceptor according to any one of item 4. (6) A patent claim characterized in that a barrier layer made of an amorphous material or a semiconductor material in which at least a portion thereof is microcrystalline is formed between the conductive support and the photoconductive layer. The electrophotographic photoreceptor according to item 1. (7) The electrophotographic photoreceptor according to claim 6, wherein the barrier layer contains at least one element selected from elements belonging to Group III and Group V of the periodic table. . (8) The electrophotographic photoreceptor according to claim 6 or 7, wherein the barrier layer contains at least one element selected from carbon, oxygen, and nitrogen. (9) The electrophotographic photoreceptor according to claim 1, wherein a surface layer is formed on the photoconductive layer.