JPS6228759A - Photosensitive body - Google Patents

Abstract

PURPOSE:To improve the mechanical and the optical properties and the stability of the titled body by laminating the prescribed layers composed of such as a specific amorphous hydrogenated silicon (a-Si:H) etc. respectively. CONSTITUTION:An electric charge blocking layer 44 composed of a-Si:H contg. at least one kind atom selected from a carbon, a nitrogen, and an oxygen atoms, an electric charge transfer layer 42 composed of a-Si:H contg. the carbon atom and an electric charge generating layer 43 composed of a-Si:H are laminated on a substrate 41. And the intermediate layer 46 composed of a-Si:H contg. at least one kind atom selected from the carbon, the nitrogen and the oxygen atoms and dopped with the group IIIa or Va element of the periodic table, and the surface reforming layer 45 contg. large amounts of atom is laminated on the substrate 41 to form the photosensitive body 39. By providing the layers 45 and 46, the mechanical strength of the titled body becomes large. The adhesive property, the anti-fatigue property against a light and the anti-chemical stability of the layers 45 and 43 are improved. The effects as prescribed above are obtd. by merely using a fluorinated silicon or by jointly using the fluorinated silicon and the prescribed silicon.

Description

[Detailed description of the invention]

B. Industrial Application Field The present invention relates to a photoreceptor, for example, an electrophotographic photoreceptor. Conventional technology Conventionally, as an electrophotographic photoreceptor, Se or As in Se,
Photoreceptors doped with Te, Sb, etc., photoreceptors in which ZnO or CdS is dispersed in a resin binder, and the like are known. However, these photoreceptors have problems in terms of environmental pollution, thermal stability, and mechanical strength. On the other hand, electrophotographic photoreceptors using amorphous silicon (a-sD as Rh) have been proposed in recent years.a
-3i has a so-called dangling bond in which the bond of 5i-3i is broken, and many localized levels exist within the energy gap due to this defect. For this reason, hopping conduction of thermally excited carriers occurs, resulting in a small dark resistance, and photoexcited carriers are trapped in localized levels, resulting in poor photoconductivity. Therefore, the above defects are replaced by hydrogen atoms (H
) to bond H to Si to fill the dangling bonds. Such amorphous hydrogenated silicon (hereinafter referred to as a-8
It is called i:H. ) has a resistivity in the dark of 108 to 10
9 Ω-cm, which is about 1/10,000 times lower than that of amorphous Se. Therefore, a photoreceptor made of a single layer of a-3t:F has problems in that the dark decay rate of the surface potential is high and the initial charging potential is low. However, on the other hand, when irradiated with light in the visible and infrared regions, the resistivity is greatly reduced, so it has extremely excellent properties as a photosensitive layer of a photoreceptor. Figure 8 shows a-3i with the above a-5i:H as the base material.
An electrophotographic copying machine incorporating a system photoreceptor 9 is shown. According to this copying machine, a glass document mounting table 3 on which a document 2 is placed and a platen cover 4 that covers the document 2 are disposed in the upper part of a cabinet 1. Below the document table 3,
An optical scanning table consisting of a first mirror unit 7 equipped with a light source 5 and a first reflecting mirror 6 is provided so as to be movable linearly in the left-right direction of the drawing, and the optical path length between the document scanning point and the photoreceptor is kept constant. The second mirror unit 20 moves according to the speed of the first mirror unit, and the reflected light from the document table 3 passes through the lens 21 and the reflection mirror 8 onto the photosensitive drum 9 as an image carrier. The light enters in a slit shape. Around the drum 9, a corona charger 10,
A developing device 11, a transfer section 12, a separation section 13, and a cleaning section 14 are arranged, and the copy paper 18 fed from the paper feed box 15 via each paper feed roller 16, 17 is further processed after the toner image on the drum 9 is transferred. The image is fixed by the fixing unit 19 and then ejected to the tray 35. In the fixing section 19, the developed copy paper is passed between a heating roller 23 containing a heater 22 and a pressure roller 24 to perform a fixing operation. However, photoreceptors with a-3i:H surfaces are susceptible to surface chemical stability, such as the effects of long-term exposure to the atmosphere or moisture, and the effects of chemical species generated by corona discharge. , has not been sufficiently investigated so far. For example, items that have been left for more than a month will be affected by moisture.
It is known that the receptor potential is significantly reduced. On the other hand, amorphous hydrogenated silicon carbide (hereinafter a-3iC:H
It is called. ), its manufacturing method and existence are described in "Ph1l. Mag, Vol. 35" (1978), etc., and its characteristics include high heat resistance and surface hardness, and a Dark resistivity (10'2
~10'3 Ω-cm), and that the optical energy gap changes over a range of 1.6 to 2.8 eV depending on the amount of carbon. However, there is a drawback that the long wavelength sensitivity becomes poor due to the widening of the band gap due to the inclusion of carbon. An electrophotographic photoreceptor combining such a=sic:H and a-3i:H has been proposed, for example, in Japanese Patent Laid-Open No. 127083/1983. According to this, a-3i:H
The layer is a charge generation (photoconductive) layer, and below this charge generation layer is a
-3iC:H layer is provided, the upper layer a-3t:H provides photosensitivity in a wide wavelength range, and the lower layer a-3iC:H forming a heterojunction with the aSi:H layer improves the charging potential. We are trying to However, the dark decay of the aSisH layer cannot be sufficiently prevented, and the charging potential is still insufficient to be of practical use.
: The presence of HIiJ causes poor chemical stability, mechanical strength, heat resistance, etc. On the other hand, in Japanese Patent Application Laid-open No. 57-17952, a Si
A first a-5iC:H layer is formed as an intermediate layer on the charge generation layer made of :H, and a second a-3iC:H layer is formed on the back surface (support electrode side). In addition, as related to this known technology,
As seen in Japanese Patent No. 23543, a gradient layer (a-5it-X CX:H) is provided between the charge generation layer and the first and second a-3iC:H layers, and the gradient layer In a-3i:H side, X=o, a-5iC:
A photoreceptor in which X=0.5 on the H layer side is known. However, when the present inventor conducted a study on the above-mentioned known photoreceptor, it was found that the effect of providing the intermediate layer is not so great, especially in continuous repeated use. That is, during continuous running of 200,000 to 300,000 times, the a-SiC layer on the surface is mechanically damaged after about 70,000 to 80,000 times, and this causes white streaks and white spots as image defects, so the rigidity resistance is sufficient. isn't it. Furthermore, light resistance fatigue occurs during repeated use, image blurring occurs, and the electrical and optical characteristics are not always stable, and the effects of the use environment (temperature, humidity) cannot be ignored. It is also necessary to further improve the adhesion between the intermediate layer and the charge generation layer. C1 Object of the invention The object of the invention is to provide excellent adhesion between the intermediate layer and the charge generation layer, resistance to mechanical damage, excellent rigidity resistance, and stable image quality without image deletion. It is an object of the present invention to provide a photoreceptor which has little optical fatigue during repeated use, has a low residual potential, and whose characteristics are stable regardless of the usage environment (temperature, humidity). 28 Structure of the invention and its effects, namely, the present invention provides a charge pro-noking layer consisting of at least one of carbon atoms, nitrogen atoms, and oxygen atoms; amorphous hydrogenated and/or fluorinated silicon; a charge generation layer made of fluorinated silicon containing carbon atoms; doped with an element of group Ma or group Va of the periodic table and at least one of carbon atoms, nitrogen atoms and oxygen atoms; amorphous hydrogenation and/or An intermediate layer made of fluorinated silicon; and an intermediate layer made of amorphous hydrogenated and/or fluorinated silicon containing more at least one of carbon atoms, nitrogen atoms, and oxygen atoms than the intermediate layer are laminated in sequence. This relates to a photoreceptor. According to the present invention, since the intermediate layer contains at least one atom of carbon, nitrogen, and oxygen, it is resistant to mechanical damage, and there is no deterioration in image quality due to white streaks, etc.
It has excellent rigidity. Furthermore, in the present invention,
Since the impurity-doped intermediate layer is provided between the intermediate layer and the charge generation layer, the adhesion between the intermediate layer and the charge generation layer is improved. In addition, since the intermediate layer and intermediate layer are provided on the charge generation layer, in addition to the above, it has excellent resistance to light fatigue during repeated use, and there is no image fading (residual potential is also reduced, and electrical and optical It has been confirmed that the electrostatic properties are always stable and are not affected by the usage environment. E. Examples The present invention will be explained in detail with reference to examples below. This shows an a-3i electrophotographic photoreceptor 39.This photoreceptor 39 is an AI
A-3t:H (which is heavily doped with a Group Va element of the periodic table (for example, phosphorus) and contains at least one of C, N, and 0) is placed on a drum-shaped conductive support substrate 41 such as
-S 1(C)(N)(0):H. ) and the 1st ff of the periodic table.
A group a element (e.g. boron) is lightly doped to make it intrinsic.
: Represented as H. ), and a-3i
: A charge-generating N (without impurity doping or made intrinsic) consisting of H 43, and a P type or N0 type heavily doped with an element of group Ha or group Va of the periodic table, and C,N , an intermediate layer 46 made of amorphous hydrogenated silicon containing at least one of O, and doped with an element of Group Ma or Group Va of the periodic table to be P-type or N-type or intrinsic (or without impurity doping). And N,
Amorphous hydrogenated silicon containing at least one of C and 0 (this is a-S 1(C)(N)(0):
It is expressed as H. ) and a layered intermediate layer 45. The charge generation layer 43 has a dark resistivity ρ. and resistivity ρ during light irradiation
The ratio to L is sufficiently large as an electrophotographic photoreceptor, and the photosensitivity (particularly to light in the visible and infrared regions) is good. In addition, when the carbon atom content of each of the above layers is in the range of 0 to 70%, the optical energy gap (
Since there is a substantially linear relationship with Eg, opt), the carbon atom content can be defined by replacing it with the optical energy gap. In addition, if the carbon atom content of a-3iC:H is appropriately selected, remarkable effects such as an increase in specific resistance and an improvement in charging potential holding ability can be obtained as shown by curve a in FIG. 3. That is, as shown by curve a in FIG. 3, when the carbon atom content is 30
When ~90% a-3iC:H is used, its resistivity varies with carbon content and is greater than or equal to IQIZΩ-cm. The above tendency is that a-3iN containing N or 0 instead of carbon
: H, a-5iO: The same applies to H. The above-mentioned film 45 is indispensable for modifying the surface of the photoreceptor and making the a-3i-based photosensitive material practically excellent. That is, it enables the basic operations of an electrophotographic photoreceptor, such as charge retention on the surface and attenuation of the surface potential due to light irradiation. Therefore, the repetitive characteristics of charging and optical attenuation become very stable, and good potential characteristics can be reproduced even if left for a long period of time (for example, one month or more). On the other hand, in the case of a photoreceptor having a-3i:H as its surface, it is easily affected by humidity, air, ozone atmosphere, etc., and the potential characteristics change significantly over time. In addition, since the layer 45 has a high surface hardness, it has abrasion resistance during processes such as development, transfer, and cleaning, and also has good heat resistance, so it is possible to apply heat-applying processes such as adhesive transfer. In order to comprehensively achieve the above excellent effects, it is important to select the composition of the layer 45. That is, when containing carbon atoms, Si + C = 100a
When atomic% (hereinafter, atomic% is simply expressed as %), 1%≦(C)590%, furthermore 10%≦
(C) Desirably 670%. Due to this C content, the above-mentioned resistivity becomes the desired value, and the optical energy gap becomes approximately 2.5 eV or more, and the irradiated light becomes a- 3i: It becomes easier to reach the H layer (charge generation layer) 43. However, if the C content is 1% or less, disadvantages such as mechanical damage occur, and the specific resistance tends to fall below a desired value, and a portion of the light is absorbed by the surface layer 45, reducing the photosensitivity of the photoreceptor. It becomes easier to decrease. In addition, if the C content exceeds 90%, the amount of carbon in the layer increases, and semiconductor properties are likely to be lost, and the deposition rate when forming an a-3iC:H film by a glow discharge method is likely to decrease. The C content is preferably 90% or less. Similarly, in the case of the layer 4S containing nitrogen or oxygen, 1%≦(N)590% (furthermore, 1O%≦[N357
0%) is better, 0% less [o) 670% (even 5%≦
[03530%] is good. In order to improve the charging ability, the surface-modified N45 may be made to have a high resistance. For this purpose, the intermediate layer may be made intrinsic. In positively or negatively charged use, the intermediate layer may be of P or N type in order to facilitate the injection of electrons or holes into the intermediate layer and to minimize the residual potential. The amount of impurity doped in each case (at the time of glow discharge decomposition described later) may be as follows. Intrinsic: Bz)Is/5iHi 2~50 Capacity ppmP type: BJ6/5iH450~1000N
Type: PHz /5iHa 1~100Q”
Moreover, the layer 45 is a-3iC○, a-3iNOs a-5
It is also important to select the film thickness within the range of 400≦t≦5000 (particularly 400≦t<2000. That is,
If the film thickness exceeds 5000, the residual potential vR
becomes too high and also causes a decrease in photosensitivity, tending to lose good characteristics as an a-3i type photosensitive photosensitive material. Also, the film thickness was increased to 40
If the number is less than 0, charges will not be charged on the surface due to the tunneling effect, resulting in an increase in dark decay and a decrease in photosensitivity. The intermediate N46 is provided to improve sensitivity, reduce residual potential, improve adhesion of the intermediate layer, and stabilize the image. In order to improve the above characteristics, it is necessary to make it P or N type. The impurity doping amount is (PH:l)/(SiHa)=
1-1ooo <preferably 10-500) Capacity ppm
, (BzH6)/(SiH4)=10~1000 (
Preferably, the volume may be 50 to 500 ppm. The content of C, N, and C in the intermediate layer 46 is preferably 0<(C)510%, 0<(N)510%, and 0<(0)55%. The thickness of this intermediate layer is preferably 50 to 5,000 people, but if it exceeds 5,000 people, the same phenomenon as described above is likely to occur, and if it is less than 50 people, the effect as an intermediate layer will be poor. Regarding the charge generation layer 43, in order to improve the charging ability,
The resistance of the charge generation layer may be increased. For this purpose, the charge generation layer may be made intrinsic. For this intrinsicization, B, H
,/5tH4=1 to 20 ppm by volume. Further, the charge generation layer has a thickness of 1 to 10 μm, preferably 5 to 7 μm.
It is better to set it as I. If the thickness of the charge generation layer 43 is less than 1 μm, the photosensitivity will not be sufficient, and if it exceeds 10 μm, the residual potential will increase, which is insufficient for practical use. The charge transport layer 42 may be made intrinsic as necessary in order to optimize charging ability and sensitivity. The doping amount for making it intrinsic is (BzH6)/(SiHi
)-2 to 20 ppm by volume is optimal. However, since the above value depends on the C concentration, it is not necessarily limited to the above value. The thickness of the charge transport layer is preferably 10 to 30 μl. In addition, the composition of the charge transport layer is 1% [C]
530%, preferably 10%≦(C) 530%. In addition, the charge blocking layer 44 may be made of elements of Group Va of the periodic table (for example, phosphorus), if necessary, to sufficiently prevent the injection of holes from the substrate 41 and to improve sensitivity and charging ability.
is doped by glow discharge decomposition to make it intrinsic, and further to N-type (
Furthermore, it becomes N° type). The doping amount is controlled by the composition of the blocking layer as follows. a-3iC or a-3iCO: Intrinsic BzHb/5in
42 to 20 volumes 1 ppm N-type (N”) Pl (+/5i
n41~1000 a-SiN or a-SiNO:
Intrinsic BJb/5iH41~2000 ”N type (N
) Plh/Sit+41 to 2000 The blocking layer may be a compound such as Sin or Sing. Also, the blocking layer 44 preferably has a thickness of 500 to 2 μm. If it is less than 500 μm, the blocking effect is weak;
Moreover, if it exceeds 2μ, the charge transport ability tends to deteriorate. The composition of the blocking layer 44 is preferably as follows. That is, 1%〈〔03590%, preferably 10%≦(C) 570%, and 1% [N369
0%, preferably 10% [N] 570%, 0
%≦

[0]≦70%, preferably O%≦

[0]≦30%
It is better to Note that each of the above layers needs to contain hydrogen. In particular, the hydrogen content in the charge generation layer 43 is essential to compensate for dangling bonds and improve photoconductivity and charge retention, and is preferably 10 to 30%. This content range also applies to the intermediate layer 45, blocking layer 44, and charge transport layer 42. Further, as an impurity for controlling the conductivity type, in addition to boron, elements of the ma group of the periodic table such as A1, Ga, In, and T1 can be used to make the conductivity type P-type. In addition to phosphorus, for N-type conversion, AS%s
Group Va elements of the periodic table, such as B, can be used. Next, a method for manufacturing the above-mentioned photoreceptor (for example, drum-shaped) and an apparatus therefor (glow discharge apparatus) will be explained with reference to FIG. A drum-shaped substrate 41 is vertically rotatably placed in a vacuum chamber 52 of this device 51, and a heater 55 is used to rotate the substrate 41.
can be heated to a predetermined temperature from the inside. A cylindrical high frequency electrode 57 with a gas outlet 53 is disposed around and facing the substrate 41, and a glow discharge is generated between the electrode 57 and the substrate 41 by a high frequency power source 56. In addition, 62 in the figure is a supply source of SiH4 or a gaseous silicon compound, 63 is a supply source of hydrocarbon gas such as CHa, and 64 is a supply source of NZ
65 is a supply source of oxygen compound gas such as 02, 66 is a carrier gas supply source such as Ar,
Reference numeral 67 indicates an impurity gas (for example, BzHb> supply source, and 68 indicates each flow meter. In this glow discharge device, first, the surface of a support, for example, an Al substrate 41, is cleaned, and then placed in a vacuum chamber 52, and The gas pressure in the tank 52 is 1O-6
The substrate 41 is evacuated and adjusted so that the
at a predetermined temperature, especially 100 to 350°C (preferably 150°C)
-300°C). Next, using a high-purity inert gas as a carrier gas, S i Ha or a gaseous silicon compound, CH4, N2.
A high frequency voltage (for example, 13.56
MHz) is applied. As a result, each of the above reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41, and N
"Type a SiC: H,, i type a-3iC: H, a-
3i: H% P” or N゛ type a 5iCQ: H,
a-3iCO: H above layer 44.42.43.46
．． 45 (i.e., eg, corresponding to the example of FIG. 1). In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-3t layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. . In addition, when forming the above a-3i photoreceptor photosensitive layer,
In order to compensate for dangling bonds, it is necessary to use fluorine instead of the above-mentioned H or in combination with H.
etc., a St : F %a-3t
:H:F% a-3iN:F. a-3iN:H:FSa-3iC:F. It can also be a-3iC:H:F. In this case, the amount of fluorine is preferably 0.5 to 10%. The above manufacturing method is based on the glow discharge decomposition method, but there are also sputtering methods, ion blating methods, and methods in which Si is evaporated while introducing activated or ionized hydrogen in a hydrogen discharge tube. (In particular, Japanese Patent Application Laid-Open No. 56-78413 (Patent Application No. 54-15) filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 2455). Hereinafter, the present invention will be described with reference to specific examples. By glow discharge decomposition method, the first
An electrophotographic photoreceptor having the structure shown in the figure was manufactured. That is, first, after cleaning the surface of a support, for example, a drum-shaped Af substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 shown in FIG. 4, and the gas pressure in the vacuum chamber 52 is set to 10.
Torr, and exhaust the air, and keep the substrate 41 at a predetermined temperature, particularly 100 to 350°C (preferably 150°C).
-300°C). Next, high-purity Ar gas was introduced as a carrier gas, high-frequency power with a frequency of 13.56 MHz was applied under a back pressure of 0.5 Torr, and preliminary discharge was performed for 10 minutes. Next, a reaction gas consisting of S i Ha and PH3 was introduced, and the flow rate ratio was 1:1:1:(1,5Xl0
-3) (Ar+SiH4+CH4 or N z + P
H3) N" type a-3iC:H layer 4 that plays a charge blocking function by decomposing the mixed gas by glow discharge
4 and a-3iC: H charge transport layer 42 at 6 μm/hr
The films were sequentially formed to a predetermined thickness at a deposition rate of . Continuing, PH
The supply of 1 and CH4 was stopped, and SiH4 was decomposed by discharge to form an a-3irH layer 43 with a thickness of 5 μm. Subsequently,
Glow discharge decomposition is performed by changing the flow rate ratio of impurity gas, an intermediate layer 46 with a changed film thickness is formed, and a-3iCO is further decomposed by glow discharge.
:H or a-3iNO:H surface protective layer 45 was further provided to complete the electrophotographic photoreceptor. As a comparative example, a photoreceptor without an intermediate layer was created. The structure of the photoreceptor thus produced was summarized as follows. (1) 1 intermediate layer: a-3iNO: H or a-3iC
O: H (2), intermediate layer: doping amount, film thickness change (see Figure 5) (
3), a-3i: H charge generation layer: film thickness = 5 μm (4
), a -SiC: H charge transport layer: film thickness = 15 μmC
Content = 11% (5), a-SiC: H or a-3iN:H charge blocking layer: Film thickness = 0.5 μm C content = 11% (6), Support: A2 cylinder (mirror polished finish) Next, various tests were conducted using each of the photoreceptors described above as follows. As shown in Figure 6, the 0,
3 Apply a load W to the R diamond needle 70 and rotate the photoreceptor with the motor 71 to scratch it. Next, the electrophotographic copying machine U
- Image is produced using a modified Bix1600 (manufactured by Konishiroku Photo Industry Co., Ltd.), and the scratch strength (g) of the photoreceptor is determined by the load at which white streaks appear on the image. After acclimatizing the photoreceptor in a modified electrophotographic copying machine U-Bix 4500 (manufactured by Konishiroku Photo Industry Co., Ltd.) for 24 hours in an environment with a typical temperature of 33°C and a relative humidity of 80%, the developer, paper,
After 1000 copies were made without contact with the blade, an image was produced and the degree of image blurring was determined based on the following criteria. ◎: There is no image blurring, and the reproducibility of 5.5-point alphabetic characters and thin lines is good. 0: 5.5 point letters become slightly thicker. △: 5.5 point letters are crushed and difficult to read. X: 5.5 point English letters are illegible. Retention position Vi (V) U By measuring the potential using a modified Bix2500, 40
The surface potential of the photoreceptor that remains even after being irradiated with static eliminating light 301 ux·sec having a peak at 0r+m. Development was measured with a 360SX type electrometer (manufactured by Trek) using a modified U-Bix 2500 machine (manufactured by Konishi Roku Photo Industries Ltd.) with a photoconductor inflow current of 200 μA and no exposure. The previous surface potential. Half-exposure E2/1 (lux-sec) Using the above device, sharply cut the long wavelength component of 620 nm or more of the image exposure wavelength using a guichroic mirror (manufactured by Genshui Kogaku Co., Ltd.), and reduce the surface potential from 500 to 250 ■The amount of exposure required to reduce the amount of light by half. The results are summarized in Figure 7. From these results, it can be seen that if a photoreceptor is produced based on the present invention, a photoreceptor excellent in each performance for electrophotography can be obtained.

[Brief explanation of drawings]

1 to 7 show examples of the present invention, in which FIG. 1 is a fri view of an a-3i photoreceptor, and FIG. 2 is an a-3i photoreceptor.
A graph showing the optical energy gap of 3iC, Fig. 3 is a graph showing the a-3iCO resistivity, Fig. 4 is a schematic cross-sectional view of the glow discharge device, Fig. 5 is a table showing the layer structure of each photoreceptor, FIG. 6 is a schematic diagram of a scratch strength tester, and FIG. 7 is a table showing the characteristics of each photoreceptor. FIG. 8 is a schematic sectional view of a conventional electrophotographic copying machine. In addition, in the reference numerals shown in the drawings, 39----------a-3i-based photoreceptor 4
−−−−−−−One support (substrate) 42・−・・−・−・
-Charge transport layer 43--Charge generation layer 44--N Load 7'' Locking layer 45--
--------...Middle layer 46 --------...Middle layer. Agent Patent Attorney Hiroshi Aisaka Figure 2 a-9i+-xCx:Hx Figure 3 Figure 6 Figure 4

Claims (1)

[Claims] 1. A charge blocking layer made of amorphous hydrogenated and/or fluorinated silicon containing at least one of carbon atoms, nitrogen atoms and oxygen atoms; and a charge blocking layer made of amorphous hydrogenated and/or fluorinated silicon containing carbon atoms; a charge transport layer consisting of; a charge generation layer consisting of amorphous hydrogenated and/or fluorinated silicon;
an intermediate layer consisting of amorphous hydrogenated and/or fluorinated silicon doped with a group IIa or group Va element and containing at least one of carbon atoms, nitrogen atoms and oxygen atoms; carbon atoms, nitrogen atoms and oxygen atoms; A photoreceptor comprising a surface-modified layer made of amorphous hydrogenated and/or fluorinated silicon containing at least one type of atoms in a larger amount than the intermediate layer.