JPS60203959A - Photosensitive body - Google Patents

Abstract

PURPOSE:To increase and stabilize the electrostatic chargeability of a photosensitive body and to improve the optical fatigue characteristics by incorporating a specified amount of O and a small amount of a IIIa group element into the charge transferring layer contg. a-SiC as a base formed under the charge generating layer contg. a-Si as a base and by forming a blocking layer contg. a large amount of a IIIa group element under the charge transferring layer. CONSTITUTION:A charge transferring layer 42 of amorphous hydrogenated and/ or fluorinated silicon carbide is formed under a charge generating layer 43 of amorphous hydrogenated and/or fluorinated silicon, and 50-500ppm O (Si+C= 100atom%) and a small amount of a IIIa group element are incorporated into the layer 42. A charge blocking layer 44 of amorphous hydrogenated and/or fluorinated silicon carbide contg. a large amount of a IIIa group element is formed under the layer 42. By incorporating O into the layer 42, the dark resistance is increased without reducing the charge transferring power, the temp. dependency of the dark resistance is controlled, and high electrostatic charge potential retentivity is provided. Since the implantation of electrons from a substrate 41 is hindered by forming the blocking layer 44 under the layer 42, a photosensitive body suitable for positive electrostatic charge is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to a photoreceptor, for example, an electrophotographic photoreceptor for positive charging.

2. Prior art Conventionally, as an electrophotographic photoreceptor, Se1 or Se has A8,
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-8t) as the entire matrix have been proposed in recent years. a-8t has a so-called dangling bond in which the 5i-8i bond 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 dangling bonds are filled by compensating the defects with hydrogen atoms (H) and bonding H to Si.

Such amorphous hydrogenated silicon (hereinafter referred to as a-8
It is called t:H. ) has a resistivity of 108 to 109 in the dark.
Ω-m, which is about 1 compared to amorphous Se.
It's even lower than 1/10,000. Therefore, a photoreceptor made of a single layer of a-8i:H 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 decreases significantly, so it has extremely excellent properties as a photosensitive layer of a photoreceptor.

Figure 1 shows a-8i with the above a-8i:H as the base material.
An electrophotographic reproduction machine incorporating a system photoreceptor is shown.

According to this copying machine, in the upper part of the cabinet 1 net 1,
A glass document mounting table 3 on which the document 2 is placed and a platen cover 4 that covers the document 2 are arranged. 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 reflection mirror 6 is provided so as to be movable linearly in the horizontal direction of the drawing. A second mirror unit 20, which maintains a constant optical path length, moves in accordance with the speed of the first mirror unit, and the reflected light from the document table 3 passes through the lens 21 and the reflecting mirror 8. The light is incident on a photosensitive drum 9 as an image carrier in a slit shape. A corona charger 10, a developing device 11, a transfer section 12, a separating section 13, and a cleaning section 14 are arranged around the drum 9, and paper is fed from a paper feed box 15 via each paper feed roller 16 and 17. After the toner image is transferred from the drum 9, the copy paper 18 is further fixed in a fixing section 19, and is discharged to a tray 35. In the fixing section 19, a fixing operation is performed by passing the developed copy paper between a heating roller n having a built-in heater 22 and a pressure roller n.

However, photoreceptors with a-8i: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, it is known that if a device is left for more than a month, it will be affected by moisture and its receptive potential will drop significantly. On the other hand, regarding amorphous hydrogenated silicon carbide (hereinafter referred to as a-8iC:H), its manufacturing method and existence are 'Ph11. M
AG, Vol. 35'' (1978), etc., and its characteristics include high heat resistance and surface hardness, a-
8t: High dark resistivity (1012 to 101
It is known that the optical energy gap changes over a range of 1.6 to 2.8 eV depending on the amount of carbon. However, the inclusion of carbon widens the bandgap, resulting in poor long-wavelength sensitivity.

An electrophotographic photoreceptor combining such a-8iC:H and a-8i:H has been proposed, for example, in Japanese Patent Laid-Open No. 127083/1983. According to this, a-8i:H
The layer is a charge generation (photoconductive) layer, and below this charge generation layer is a
A functionally separated two-layer structure was created in which the -8iC:H layer was provided as a charge transport layer, and the upper layer a-8t:H obtained photosensitivity in a wide wavelength range, and the a-8i:H layer The charging potential is improved by the lower layer a-8iC:H that forms a heterojunction with the a-8iC:H layer. However, the dark decay of the a-8t:H layer cannot be sufficiently prevented, the charging potential is still insufficient and it is not practical, and the a-8i:H layer is present on the surface. chemical stability, mechanical strength,
Heat resistance etc. become poor.

On the other hand, JP-A-57-17952 discloses a-8i:
A first a-8iC:H layer is formed as a surface modification layer on the charge generation layer made of H, and a second a-8iC:H layer is formed on the back surface (support electrode side).
The a-8iC2H layer is formed as a charge transport layer to provide a functionally separated three-layered photoreceptor.

However, in known photoreceptors, especially a-8iC
It has been found that the :H charge transport layer has the following problems.

That is, although the known a-8iC:H has sufficient charge transport ability (carrier range (μτ) e = mobility x lifetime) and charge retention ability (dark resistance ρp), the temperature dependence of ρ0 is large; For this reason, the charging potential retention characteristics deteriorate at high temperatures, making it impossible to put it to practical use.

3. Purpose of the Invention The purpose of the present invention is to provide a photoreceptor that can stably maintain a high charging potential (especially at high temperatures or high humidity), has excellent optical fatigue properties, and is suitable for positive charging. .

4. Structure of the invention and its effects, that is, the photoreceptor according to the invention has a charge transport layer made of amorphous hydrogenated and/or fluorinated silicon carbide under a charge generation layer made of amorphous hydrogenated and/or fluorinated silicon. In the photoreceptor in which the charge transport layer is provided with 50 to 500 ppm of oxygen (however, the total number of silicon atoms and carbon atoms is 100 atomic
%. ) and a relatively small amount of an element of Group IIIa of the periodic table, and below the charge transport layer, the charge transport layer is made of amorphous hydrogenated and/or fluorinated silicon carbide and contains a relatively small amount of an element of Group IA of the periodic table. It is characterized by being provided with a charge blocking layer containing a large amount.

According to the present invention, it is a functionally separated photoreceptor, and the charge transport layer contains 50 to 500 ppm of oxygen, so that ρ0 can be effectively improved without reducing the charge transport ability (μτ)e. ρ. temperature dependence (dρD
/dT) can be kept small. Therefore, the charging potential retention characteristics are improved, and the upper limit temperature (and the upper limit humidity) at which the photoreceptor can be used can be increased.

If the oxygen content is less than 50 ppm, the effect of oxygen content will not be exhibited, and if it exceeds 500 ppm, there will be too much oxygen and the carrier mobility, that is, (μ
τ) e is significantly reduced. Therefore, it is essential to set the oxygen content to 50 to 500 ppm, and it is particularly desirable to set the oxygen content to 70 to 300 ppm.

Moreover, since this charge transport layer contains a relatively small amount of Group 1 IIa elements of the periodic table (lightly doped), it contributes to good injection of carriers from the charge generation layer to the charge transport layer. ing.

Furthermore, since a charge-promoting layer containing a relatively large amount of Group IA elements of the periodic table (heavy doping) is provided below the charge transport layer, when the photoreceptor is positively charged, the support substrate side Injection of electrons is effectively prevented, resulting in excellent charging potential retention characteristics when the photoreceptor is used for positive charging.

5. Examples Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 2 shows an a-8i electrophotographic photoreceptor 39 for positive charging according to this embodiment. This photoreceptor 39 is mounted on a drum-shaped conductive support substrate 41 such as M, etc.
a-8iC heavily doped with group elements, e.g. boron
A P-type charge blocking layer 44 made of:H, a charge transport layer 42 made of a-8iC:H, which is lightly doped with an element of group Ⅰa of the periodic table, such as boron, and contains 50 to 500 ppm of oxygen, and a- A charge generation layer 43 made of 8i:H and amorphous hydrogenated carbide or silicon nitride (a-8iC:H or a-8i
It has a structure in which a surface modification layer 45 made of an inorganic substance such as N:H) or SiOz is laminated. The charge generation layer 43 has a ratio of resistivity ρ0 in the dark to resistivity ρE during light irradiation that is sufficiently large for use as an electrophotographic photoreceptor, and has good photosensitivity (particularly to light in the visible and infrared regions).

In this photoreceptor 39, based on the present invention, a-8i
Oxygen atoms are added to the charge transport layer 42 made of C:H in an amount of 50 to 500 p per 100 atomic% of the total number of atoms of Si.
Contains pm. With oxygen in this content range, the ρD of the charge transport layer 42 is not high even under high temperature (or high humidity), and the charging potential holding ability of the photoreceptor is stably maintained.

The carbon atom content of the charge transport layer and the charge blocking layer is preferably 10 to 30 atomic % (the total number of atoms in S i 10 is 100 atomic %), and the film thickness of the charge transport layer is preferably 10 to 30 atomic %. is 10-30
It is appropriate to set it to μm.

Further, in this charge transport layer 42, an element of Group 1IIa of the periodic table, such as boron, is contained at a flow rate ratio of B2H6/S1H4=
Lightly doped by glow discharge decomposition at 1 to 20 ppm.

In order to sufficiently prevent the injection of electrons from the substrate 41, the charge blocking layer 44 contains an element of group 111a of the periodic table (for example, boron) at a flow rate ratio of BzHs/5iH4=100 to 5.
It is preferable to dope it at 000 ppm to make it P type (or even P type).

Regarding the thickness of each layer described above, the charge generation layer 43 has a thickness of 1 to 1.
The 5 μm 1 blocking layer 44 preferably has a thickness of 400× to 2 μm (preferably 400 to 500×).

If the thickness of the charge generation layer 43 is less than 1 μm, the photosensitivity will not be sufficient, and if it exceeds 5 μm, the residual potential will increase, which is insufficient for practical use. If the thickness of the blocking layer 44 is less than 400X, the blocking effect will be weak, and if it exceeds 2 μm, the charge transport ability will likely be poor.

The surface-modified layer 45 is formed by modifying the surface of the photoreceptor.
It is preferable to provide this in order to make the photoreceptor of the system practically superior. 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 are very stable, and good potential characteristics can be reproduced even if left for a long period of time (for example, one month or more). In the case of a photoreceptor having a-8t:H on its surface, it is susceptible to the effects of humidity, air, ozone atmosphere, etc., and its potential characteristics tend to change over time. Also, a
-8iC:H or a-8tN:H surface modification layer 4
Since No. 5 has a high surface hardness, it has poor abrasion resistance in processes such as development, transfer, and cleaning, and also has good heat resistance, so it can be applied to processes that apply heat such as adhesive transfer.

In order to achieve such excellent effects comprehensively, a-
It is important to choose a carbon or nitrogen composition of 8iC:H or a-8iN:H. That is, the carbon or nitrogen atom content was set to Si+C (or N) = 100%! It is desirable that the amount is 10 to 70 atomic%.
When the C or N content is 10 or more, the specific resistance described above will not reach the desired value, and the optical energy gap will be approximately 2. At OeV or more, the irradiated light easily reaches the a-8i:H layer (charge generation layer) 43 due to the so-called optically transparent window effect for visible and infrared light. However, C
Alternatively, if the N content is less than 10 inches, the specific resistance tends to fall below the desired value, and a portion of the light is absorbed by the surface layer 45.
The photosensitivity of the photoreceptor tends to decrease. Furthermore, if the C or N content exceeds 70%, the amount of carbon or nitrogen in the layer is large, and the semiconductor properties are likely to be lost. The C or N content is preferably 70% or less since the deposition rate tends to decrease when forming the oxide.

It is also important to select the thickness of the a-8iC:H or a-8iN:H layer 45 within the range of 400X≦t≦5000X (particularly 400X≦t<2000X).
That is, if the film thickness exceeds 5000 K, the residual potential VR becomes too high and the photosensitivity decreases, resulting in a-
It is easy to maintain the good characteristics of an 8i photoreceptor.

In addition, if the film thickness is less than 400 layers, the tunnel effect will prevent the charge from being charged on the surface, resulting in an increase in dark decay and a decrease in photosensitivity. It is necessary to.

In particular, the hydrogen content in the charge generation layer 43 is essential for compensating for dangling bonds and improving photoconductivity and charge retention.
'16 is desirable. This content range also applies to the surface modification layer 45, blocking layer 44, and charge transport layer 42. In addition to boron, other impurities such as At, Ga, In, and Tt in the periodic table may be used as impurities to control the conductivity type of the blocking layer 44 to make it P-type, or as doping impurities to the charge transport layer 42. Group 1IIa elements 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.

Inside the vacuum chamber 52 of this device 51, a drum-shaped substrate 41
is set so as to be vertically rotatable, and the substrate 4 is heated by a heater 55.
1 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 high-frequency power source 56 generates a jiglow discharge between the electrode 57 and the substrate 41. In addition, 62 in the figure is a source of SiH4 or a gaseous silicon compound, 63 is a source of 02 or a gaseous oxygen compound,
64 is a supply source of hydrocarbon gas such as CH4 or nitrogen compound gas such as NH3, N2, 65 is a carrier gas supply source such as Ar, 66 is an impurity gas (for example, B2H6) supply source,
67 is each flow meter.

In this glow discharge device, first, the surface of a support, for example, an M substrate 41, is cleaned and then placed in a vacuum chamber 52, and the gas pressure in the vacuum chamber 52 is adjusted to 10'Torr and evacuated. , and the substrate 41 is heated to a predetermined temperature, particularly 10
Heat and maintain at 0 to 350°C (preferably 150 to 300°C). Then SiH4 or a gaseous silicon compound, B2H
6. CH4 (or NH3, N2), 0° in vacuum chamber 5
A high frequency voltage (for example 13.
56 MHz) is applied. As a result, each of the above-mentioned reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41, resulting in boron-heavy doped P-type a-8iC:H1 boron-light-doped 0-containing a-8LC:H.

a-8i:H, a-8iC:H or a-8iN:H are deposited successively (i.e. corresponding to the example of FIG. 2) on the substrate as layers 44, 42, 43, 45 as described above. .

In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-8i layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. .

In addition, in order to compensate for dangling bonds when forming the photosensitive layer of the a-8t photoreceptor, fluorine is introduced in the form of SiF4 or the like in place of the above-mentioned H or in combination with H. , a-8t:FXa-8t:H:F.

a-8iN:F Xa-8iN:H:F, a-8iC:
F, a-8iC:H:F. In this case, the amount of fluorine is preferably 0.5 to 10 atomic%.

The above manufacturing method is based on the glow discharge decomposition method, but there are also methods such as sputtering method, ion blating method, and method of evaporating St while introducing activated or ionized hydrogen in a hydrogen discharge tube. (In particular, Japanese Patent Application Laid-Open No. 56-78413 (Patent Application No. 54-152) filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 455).

FIG. 4 shows a photoreceptor according to the present invention in the above-mentioned Japanese Patent Application Laid-Open No. 56-78.
This figure shows a vapor deposition apparatus used for fabricating the film by the vapor deposition method of No. 413.

A vacuum pump (not shown) is connected to the Pel jar 71 via an exhaust pipe 73 having a butterfly valve 72, and the inside of the Pel jar 71 is thereby pumped with, for example, 10-3 to 10
"Torr high vacuum state. The Pelger 7 concerned
A substrate 41 is placed in the chamber 1 and heated by a heater 75 to a temperature of 100 to 350°C, preferably 150 to 300°C, and a DC power supply 76 is heated to a temperature of 0 to -1.
A negative DC voltage of 0 KV, preferably -1 to -6 KV is applied. a-8i: To form the H layer 43, while introducing active hydrogen and hydrogen ions into the Pel jar 71 through a hydrogen gas discharge tube 77 connected to the Pel jar 71 so that its outlet faces the substrate 41, A silicon evaporation source 78 provided to face the substrate 41 is heated and the upper shutter S is opened. To form the a-8iC:H layer 45, silicon is evaporated under the supply of CH4. To form the charge blocking layer 44, the cricon 78 and aluminum 79 may be evaporated. 0 containing a-8
The iC:H layer 42 can be formed by further supplying oxygen gas. It is preferable to activate CH4,0□ via the discharge tube 70 and introduce it as appropriate.

For example, the structure of the discharge tube 77, 70 is shown in FIG. 5, as shown in FIG. , a discharge space member 84 made of, for example, cylindrical glass surrounding the discharge space 83, and another ring-shaped electrode member 86 having an outlet 85 provided at the other end of the discharge space member 84.
When a DC or AC voltage is applied between the one electrode member 82 and the other electrode member 86, for example, hydrogen gas supplied through the gas port 81 is discharged. A glow discharge is generated in the space 83, and active hydrogen and ionized hydrogen ions, which are composed of hydrogen atoms or molecules activated by simulator energy, are discharged to the outlet 85.
It will be drained out. The discharge space member 82 in this illustrated example has a double pipe structure and is configured to allow cooling water to flow therethrough, and reference numerals 87 and 88 indicate a cooling water inlet and an outlet.

89 is a cooling fin for one electrode member 82.

The distance between the electrodes in the above hydrogen gas discharge tube 77 is 10~
The applied voltage is 15 crn, and the applied voltage is 6004. The pressure in the discharge space 83 is about 1 O-2 Torr.

The present invention will now be described with reference to specific examples.An electrophotographic photoreceptor having the structure shown in FIG. 2 was prepared on a drum-shaped M support by a glow discharge decomposition method.

That is, first, after cleaning the surface of the support, for example, a drum-shaped M substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 shown in FIG. 3, and the gas pressure in the vacuum chamber 52 is set to 10 To
rr, and then heat the substrate 41 to a predetermined temperature, especially Kiooo to 350°C (preferably 150°C).
-300°C). Next, high purity Ar
A gas was introduced as a carrier gas, a high frequency power with a frequency of 13.56 Mn2 was applied under a back pressure of 5 Torr, and preliminary discharge was performed for 10 minutes. Then, SiH
By introducing a reactive gas consisting of 4, CH4, and B2H6, and decomposing the (Ar+SiH4+CH4+B2H6) mixed gas with a glow discharge at a flow rate ratio of 1:1:1:(1,5X10''), the charge blocking function is performed. A P-type a-8iC:H layer 44 was formed, and oxygen was further supplied to form a charge transport layer 42 to a predetermined thickness at a deposition rate of 6 μm/hr.Subsequently, CH4, B2H6,0
2 is stopped, SiH4 is decomposed by discharge, and a predetermined thickness of a
-8i: H layer 43 was formed. Subsequently, the flow rate ratio 4:
Glow discharge decomposition was performed with a 1:6 (Ar+SiH4+CH4) mixed gas, and an a-8iC:H surface protection layer 45 of a predetermined thickness was further provided to complete an electrophotographic photoreceptor. Using this photoreceptor, a copying machine (modified U-Bix3000 machine:
As a result of image creation using Roku Konishi Photo Industry ■),
Clear images with good resolution and gradation, high image density, and no fog were obtained. Further, even after repeated copying was performed tens of thousands of times, stable and high-quality images were continuously obtained.

That is, during the test, the electrophotographic photoreceptor produced as described above was used with an electrometer SP-428 model (
(manufactured by Kawaguchi Denki ■), the voltage applied to the discharge electrode of the charger was set to +6 KV, the charging operation was performed for 10 seconds, and the charging potential of the photoreceptor surface immediately after this charging operation was Vo (
V), and after 2 seconds of dark decay, the amount of irradiation light necessary to attenuate the charged potential to 1/2 is halved as the exposure amount E 1/
2 (lux, 5ec). The light attenuation curve of the surface potential is flat at a certain finite potential and may not be completely zero, but this potential is defined as the residual potential v, (V)
It is called.

By varying the composition of each layer, the results shown in the table below were obtained. According to this, it can be seen that when the 0 content of the charge transport layer is set to 50 to 500 ppm, the electrophotographic properties of the photoreceptor are greatly improved and the temperature dependence is reduced.

Regarding the image quality, ◎ indicates that the image is clear, ○ indicates that the image is good, and ゛Shogari field X indicates that the image quality is not practically applicable.

(I F Eizi, > moxibustion to Kenho.)

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a conventional electrophotographic copying machine. , 4. Figures 2 to 5 show embodiments of the present invention; therefore, Figure 2 is a sectional view of an a-8i photoreceptor, Figure 3 is a schematic sectional view of a glow discharge device, and Figure 4 is a schematic sectional view of a glow discharge device. The figure is a schematic cross-sectional view of a vacuum evaporation apparatus, and FIG. 5 is a cross-sectional view of a gas discharge tube. In addition, in the symbols shown in the drawings, 39......A-8i type photoreceptor 41...・・・・Support body (substrate) 42 ・・・・・・・・・・・・・・・・・・
Charge transport layer 43・・・・・・・・・・・・・・・・・・
Charge generation layer 44・・・・・・・・・・・・・・・
Charge blocking 偕45・・・・・・・・・・・・・・・
...Surface modified layer 55...
····heater%················
・・High frequency power supply 57・・・・・・・・・・・・・・・・
... Electrodes 62 to 66 ... Curved gas supply sources 70, 77 ...... Gas discharge tubes 78, 79 ... - ...Songs, songs... They are sources of evaporation. Agent: Patent attorney Hiroshi Aisaka (and 1 other person) Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A photoreceptor in which a charge transport layer made of amorphous hydrogenated and/or fluorinated silicon carbide is provided under a charge generation layer made of amorphous hydrogenated and/or fluorinated silicon, Charge transport layer is 50-500p
pm of oxygen (however, the total number of silicon atoms and carbon atoms is 100 atomic %), contains a relatively small amount of Group IIIa elements of the periodic table, and has an amorphous layer under the charge transport layer. A photoreceptor comprising a charge blocking layer made of hydrogenated and/or fluorinated silicon carbide and containing a relatively large amount of a Ha group element of the periodic table. 2. The charge transport layer contains 10-30 atom c % carbon (however, the total number of silicon atoms and carbon atoms is 10
0100ato%. ), and contains diborane and monosilane at a ratio of 1 to 20 ppp/monosilane.
A photoreceptor according to claim 1, which is formed by glow discharge decomposition under conditions of supply at a flow rate ratio of m. 3. Charge blocking layer is 10-30 atomic%
of carbon (however, the total number of silicon atoms and carbon atoms is 100 atomic%), and the silicone and monosilane are diborane/monosilane = 100~
A photoreceptor according to claim 1 or 2, which is formed by glow discharge decomposition under conditions of supply at a flow rate of 5000 ppm. 4. On the charge generation layer, the layer is not made of amorphous hydrogenated and/or fluorinated silicon carbide and has a carbon content of 10 to 7.
0 atomic % (however, the total number of silicon atoms and carbon atoms is 100 atomic %). The photoreceptor described in item 1. 5. On the charge generation layer, it is not made of amorphous hydrogenated and/or fluorinated silicon nitride and has a nitrogen content of 10 to 7.
0 atomic % (however, the total number of silicon atoms and nitrogen atoms is 100 atomic %). The photoreceptor described in item 1.