JPH01206355A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body which withstands repetitive use and with which good images are obtainable by incorporating a carbon atom and oxygen atom into a surface reformed layer and doping an impurity element under specific conditions therein. CONSTITUTION:This photosensitive body has a charge generating layer 43 consisting of amorphous silicon hydride and/or halide and a charge transfer layer 42 consisting of amorphous silicon hydride and/or carbohalide as well as the surface reformed layer 45 on the surface of either thereof. The surface reformed layer 45 consists of the amorphous silicon hydride and/or halide contg. the carbon and oxygen atoms and contg. the impurity element of group IIIA of the periodic table as well. The content of the oxygen atom is specified to 1-20atm.% (where the total content of the silicon atom and the carbon atom and oxygen atom is designated as 100atm.%) and the surface reformed layer 45 doped with the impurity element under the conditions expressed by formula I at the time of forming the surface reformed layer 45 is formed. The photosensitive body which withstands the repetitive use and with which the good images are obtd. is thereby obtd.

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, amorphous silicon (
Electrophotographic photoreceptors using a-3i) as a matrix have been proposed in recent years. Since such a-3i has so-called dangling bonds, amorphous hydrogenated silicon (a-3i: If ) has been proposed. 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 "Phi,"
Mag, Vol. 35'' (1978), etc., and its characteristics include high heat resistance and surface hardness, and high dark resistivity (compared to a-3i:H).
It is known that the optical energy gap changes over a range of 1.6 to 2.8 eV depending on the carbon content. 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-3iC:H and a-3i:H has been proposed, for example, in Japanese Patent Application Laid-Open No. 115559/1983. According to this, a-3i:H
An a-8iC:H layer is formed as a surface modification layer on the charge generation layer consisting of the following. However, when the present inventor investigated the above-mentioned known photoreceptor, it was found that even if a surface modification layer was provided, it was still not as effective as expected, and image deletion was particularly likely to occur. OBJECT OF THE INVENTION An object of the present invention is to provide a photoreceptor that can withstand repeated use and can produce good images. 21 Structure of the invention and its effects, that is, the present invention comprises: a charge generation layer made of amorphous hydrogenated and/or halogenated silicon; a charge transport layer made of amorphous hydrogenated and/or halogenated silicon carbide; Amorphous hydrogen having a surface modified layer deposited on the surface of the generation layer or the charge transport layer, the surface modified layer containing carbon atoms and oxygen atoms and also containing an impurity element of group mA of the periodic table. and/or halogenated silicon, and the amount of oxygen atoms is 1 to 20 atm% (
However, the total amount of silicon atoms, carbon atoms, and oxygen atoms is 100 atm%. ), and the impurity element is doped into the surface modified layer under the following conditions during formation of the surface modified layer by glow discharge decomposition. According to the present invention, since the surface modified layer contains carbon atoms and oxygen atoms, the mechanical strength and optical band gap (Eg, opt) of the layer become large, resulting in deterioration of image quality due to white streaks, etc. This results in excellent printing durability. Moreover, the above-mentioned impurity elements are present in the surface modified layer at 10-'
Since it is doped at a ratio of ~103 volume ffl (vol) pl", image blurring can be greatly reduced during image formation. This is because the surface resistance and impurity level of the layer are appropriately set by the above impurity elements. In addition, since the charge generation layer described above and the charge transport layer described above are provided to form a functionally separated laminated structure, the charge generation layer provides photosensitivity in a wide wavelength range. In addition, the charge transporting layer forming a heterojunction with the charge generating layer can improve charge transporting ability and charging potential. E. EXAMPLES The present invention will be explained in detail with reference to Examples below. The figure shows an a-3i electrophotographic photoreceptor 3 according to this embodiment.
9. This photoreceptor 39 is provided on a drum-shaped conductive support substrate 41 made of An, etc., as necessary.
-3i-based charge blocking layer 44, a charge transport JEJ42 made of amorphous hydrogenated silicon carbide (a-3i C: l()), and a charge generation layer made of a-3i:, H (without impurity doping or intrinsically 43
and a surface-modified layer 45 made of a-3i (Co):H containing C and 0. The charge blocking layer 44 is a-3t:Hla-3iC
:H or a-3iN:H, and may be doped with an element of group 11rA or group VA of the periodic table. Further, the charge transport layer 42 and the charge generation layer 43 may also be doped with similar impurities. The charge generation layer 43 has a dark resistivity ρ. The ratio of resistivity ρ when irradiated with light is sufficiently large as an electrophotographic photoreceptor, and the photosensitivity (particularly to light in the visible and infrared regions) is good. What should be noted here is that the surface modified layer 45 is made of a-3i (CO):H containing C and O. This improves the mechanical strength of the surface modified layer 45 and also improves the optical band gap. Regarding the composition of the surface modified layer 45, 10 atm%≦(C+0)≦100 atm%l
atm%≦(0)≦20 atm%
C3i) + (C) ten (0) = 100
40 atm%≦(C+O)≦70 atm%l a
tm%≦

[0] ≦ 10 atm% (S
i) + (C) 10(0) -100 atm%) (here, atm% represents the percentage of the number of atoms). If the C+O content is too low, the effect of improving scratch resistance will be poor, and if it is too high, the S
The amount of i decreases and semiconductor characteristics are likely to be lost. In addition, when the surface-modified layer contains a small amount of oxygen atoms, the optical band gearing is improved and the image fade resistance is improved, but if the amount is too large, the scratch resistance is deteriorated. Another noteworthy point of this photoreceptor is that in the glow discharge method described below, for example, CBz Hb ) / (S i H4) ~10-3
~103 volume fflppm (preferably 10-1~103
Capacity ffippm, and even 10-' to 102 capacitance ppm
m, most preferably 10 -1 to 10 ppm by volume) of Group IIA elements of the periodic table are doped into the surface modification layer 45 . Due to the inclusion of these impurity elements,
Image deletion can be significantly reduced. That is, if the amount of the impurity element is less than 10 4 volume ppm, it is too small, and if it exceeds 10 3 volume ppm, it is too large, and in both cases, a sufficient surface resistance cannot be obtained and image blurring occurs significantly. Further, the thickness of the surface modified layer 45 is desirably 200 to 50,000, more preferably 1,000 to 10,000. If the film thickness is too large, the residual potential (8) will become too high and the photosensitivity will decrease, resulting in a-3
It is easy to lose good characteristics as an i-type photoreceptor, and if the film thickness is too small, charges will not be charged on the surface due to the 1-channel effect, resulting in an increase in dark decay and a decrease in photosensitivity. The charge generation layer 43 may be composed of a-3i:H, and its composition is preferably 5 to 40 atm% of H, and when it contains halogen instead of or in combination with H. 5 to 40 atm%, or the total amount of I] and halogen is preferably 5 to 40 atm%. This charge generation layer 43 is preferably doped with an impurity, particularly an element from Group IIIA or VA of the periodic table, to improve charging performance. For example, during glow discharge described below, CB2 H6) / (S i Ha ] = 10-3 ~
100 (preferably 10-2 to 10) Capacity ppm S(
P H2) / (S i H4] = 10-3 ~ 10
0 (preferably 10-" to 10) capacitance ppm. Also, the thickness of this layer 43 is 1 to 50 μm, preferably 5
It is preferable to set the thickness to 30 μm. If the thickness of the photoconductive layer 43 is too small, a sufficient charging potential cannot be obtained, and if it is too large, the residual potential increases, which is insufficient for practical use. The charge transport layer 42 has the functions of both potential retention and charge transport, preferably has a dark resistivity of 10'2 Ω-cm or more, has high electric field resistance, and has a potential retained per unit film thickness. In addition, the size of the energy gear can be adjusted by adjusting the carbon content (especially 5 to 30 atm%). It is possible to efficiently inject electrons generated in response to light irradiation in the charge generation layer 43 without creating a barrier. Therefore, this a-3iC:0 layer 42 maintains a high surface potential at a practical level, and -3i: It has the function of efficiently and quickly transporting charge carriers generated in the H layer 43, and making the photoreceptor highly sensitive and free of residual potential.The carbon atom content of this charge transport layer 42 is set to 5 to 30 atm.
% (furthermore, 10 to 20 atm%) (however, the total number of atoms of Si and C is 100 atm%). That is, when the carbon atom content is less than 5 atm%, a-3
iC: The specific resistance of 8 layers 2 is 1012Ω, which is necessary for potential holding ability.
-cm, the charging potential is particularly likely to be insufficient. Moreover, when the carbon atom content exceeds 30 atm%,
At the same time, the specific resistance decreases, and at the same time, the presence of too many carbon atoms increases the number of defects in the a-3iCsH layer, which tends to deteriorate the carrier transport ability itself. This layer 42 preferably contains 5 to 50 atm% of hydrogen atoms (5 to 50 atm% of halogen when containing halogen instead of or in combination with II).
Alternatively, the total amount of H and halogen is preferably 5 to 50 atm%. This layer 42 is preferably doped with an impurity, particularly an element of Group I [A or VA of the periodic table] in order to improve charging performance. For example, during glow discharge described below, [B2H6]
/ (S jH-) ~ 10-' ~ 1000 (preferably 10-'' ~ 100) Capacity ppm, CPH3) /
(S i H4) = IO~1000 (preferably 10-2~100) capacitance ppm. Further, the thickness of the charge transport layer 42 is, for example, 5 μm to 30 μm in order to pass the Carlson dry development method.
It is desirable that it is μm. If this film thickness is less than 5 μm, it is too thin and the surface potential necessary for development cannot be obtained.
Moreover, if it exceeds 30 μm, the rate of carrier reaching the support 41 will decrease. Further, in order to sufficiently prevent electron injection from the substrate 41 and improve sensitivity and charging ability, the charge blocking layer 44 is doped with a group IIIA element (for example, boron) of the periodic table by glow discharge decomposition. , to become P type (and even P+ type). It is desirable to control the doping amount as follows depending on the composition of the blocking layer. a-3i:H (H content 5-40 atm%): CBz
H6) / (S s H-) -10-3~10'
Capacity ppm (even 10-' to 10" capacity ppm) (
P H:I) / (S i H4] = 10-'~
104 volume ppm (furthermore, 10-1 to 102 volume ffip
pm) a-3iC:H (H content 5-50 atm%,
C content 5-100 atm%): (B2 H6) / (S i H4) ~10-'~
106 volume ppm (furthermore 10-1 to 104 volume ppm
)CP H3) / (S i H4) ~10-3
~106 volumesffi p p m (furthermore, 10-1~10
4 volumes l1l) III) a-5iN:H (H content 15~
50 atm%, N content 5-60 atm%): CBz H6) / (S i Ha ) ~10-3
~106 capacitance ppm (and even 10-1 to 10' capacitance ppm
n+)CP Hz) / (S i H4) ~1
0-' to 10b IJi p p m (furthermore, 10-
The blocking layer 44 preferably has a thickness of 100 to 2 μm. If the thickness is too small, the blocking effect will be weak, and if the thickness is too large, the charge transport ability will tend to deteriorate. Note that each of the above layers needs to contain hydrogen. In particular, the hydrogen content in the charge generation layer 43 is necessary to compensate for dangling bonds and improve photoconductivity and charge retention. Also, the order of the layers 42, 43 described above may be reversed. In addition to boron, the impurities to be doped include A1,
Group IV elements of the periodic table such as Ga, In-, and Tβ can be used, and in addition to phosphorus, elements of group VA of the periodic table such as As and sb can be used.
Group elements can be used. Next, a method for manufacturing the above-mentioned photoreceptor (eg, drum-shaped) and an apparatus therefor (glow discharge apparatus) will be explained with reference to FIG. A drum-shaped substrate 41 is set rotatably vertically 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, in the figure, 62 is 5i) 14 or a supply source of gaseous silicon compound, 63 is a supply source of hydrocarbon gas such as CH, 64 is N
65 is a supply source of oxygen compound gas such as 0□, 66 is a carrier gas supply source such as Ar, 67 is an impurity gas (for example, I3z H6) supply source, 6
8 is each flow meter. In this glow discharge device, first, the surface of a support, for example, an A1 substrate 41, is cleaned and then placed in a vacuum chamber 52, so that the gas pressure in the vacuum chamber 52 is 1.
The temperature is adjusted to O-6T orr and evacuated, and the substrate 41 is heated and maintained at a predetermined temperature, particularly 100 to 350"C (preferably 150 to 300"C).Next, a high-purity inert gas is heated to a carrier temperature. As a gas, SiH4 or a gaseous silicon compound, CH4, N2, CO2, 02, etc. are introduced into the vacuum chamber 52 as appropriate, and the pressure is, for example, 0.01 to 10 Torr.
A high frequency voltage (for example, 13.56 Mllz) is applied by a high frequency power supply 56 under a reaction pressure of r. by this,
Each of the above reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41 to form a-3iC:H. a-3i :H, a-3iC:H, a-3iCO:H as the above layers 44, 42, 43, 45 deposited successively (i.e. corresponding to the example of FIG. 1, for example) on the substrate. let In the above manufacturing method, the support temperature is set at 100 to 350°C in the step of forming the a-3i layer on the support, so the film quality (especially electrical properties) of the photoreceptor can be improved. . In addition, at the time of forming each layer of the a-3i-based photoreceptor,
In order to compensate for dangling bonds, it is necessary to use halogens such as fluorine instead of H, or in combination with H.
i F a etc., a-Si : F, ,
a-3i:H:F,, a-3iN:F. a-3iN:H:F, a-3iC:F. It can also be a-3iC:H:F or the like. 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 A1 substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 in FIG. 2, and the gas pressure in the vacuum chamber 52 is set to 10-
' T orr, and then heat the substrate 41 to a predetermined temperature, particularly 100 to 350°C (preferably 100°C to 350°C).
Heat and maintain at 50-300°C. Then, high-purity Ar gas was introduced as a carrier gas and the frequency was 13.56 M under a back pressure of 0.5 Torr.
tlzO high frequency power was applied and preliminary discharge was performed for 10 minutes. Next, a reaction gas consisting of SiH4, CH, and B11-16 was introduced, and the flow rate ratio was 1:L:1:(1,5
xlO-') of (Ar+S i [(,+CH40BZ
H6) P+ type a-3i C that plays a charge blocking function by decomposing the mixed gas by glow discharge:
The H layer 44 was formed to a predetermined thickness at a deposition rate of 6 pm/hr. Next, the flow rate ratio of BzHb to SiH4 was set to 1:
(6Xl0-6) and the charge transport layer 42 is 6 μm thick.
The films were sequentially formed to a predetermined thickness at a deposition rate of /hr. Subsequently, the supply of B2H6 and CH4 was stopped, and 3iH4 was decomposed by discharge to form an a-3i:H layer 43 of a predetermined thickness. Furthermore, at a flow rate ratio of 40:3:9'O (Ar:SiH
4: CH4) mixed gas at reaction pressure P = 0.5 To
rr, discharge power R, = 400 W, glow discharge decomposition is performed to form an intermediate layer of a predetermined thickness, and the flow rate ratio is 40:3.
:90:(1,5Xl0-')(Ar:S
i H4: CH4: B2 Hb) mixed gas at reaction pressure P = 1. OTorr, discharge power R, = 400
A surface protective layer 45 was further provided by glow discharge decomposition with W, and an electrophotographic photoreceptor was completed. At this time, the amount of BzHaO was varied to obtain corresponding photoreceptors. In addition, CO□ was used as an oxygen source when the surface layer 45 was made of a-3i Co, and an appropriate amount was supplied as necessary. Next, the following tests were conducted using each of the photoreceptors described above. However, in the composition of the surface modified layer of a-3iC:H (excluding B), C bond is 39J atm% and ○ amount is 5.6
ATM% (Table 1). Furthermore, the data in Table 2 was obtained by changing the amount of ○ in column 4 of Table 1 (the numbers are atm%). The photoreceptor was allowed to acclimate to a modified electrophotographic copying machine U-B 1x2500 (manufactured by Konica Corporation) for 24 hours in an environment with a temperature of 33°C and a relative humidity of 80%, and then the developer, paper, and blade were removed. After 1000 copies were made without contact with the paper, an image was printed and the degree of image blurring was determined based on the following criteria. ○: There is no image flow, and the reproducibility of 5.5-point alphabetic characters and thin lines is good. △: 5.5 point letters are crushed and difficult to read. X: 5.5 points of unreadable letters. Ranmu Mata'y L±Dan In the above, photoreceptors provided with surface-modified layers with various amounts of oxygen were prepared, and the state of scratches was observed. ○: Almost no scratches. △: 〃 Yes. ×: Very many. The results are summarized in Table 1 below. From this result, it was found that when the photoreceptors (numbers 2 to 7) were prepared according to the present invention, electrophotographic photoreceptors with significantly less image deletion were obtained. Furthermore, from Table 2, based on the present invention, < 1 kll ~
No. 13 has excellent characteristics. Table 1 Table 2 Next, as a result of experiments, it was found that the functionally separated photoreceptor according to the present invention has excellent photosensitivity and charging characteristics. The measurements were performed as follows, and the results are shown in Table 3 below. By measuring the electric potential using a modified 1x2500 machine, 4
The surface potential of the photoreceptor remains even after being irradiated with static elimination light of 301 ux-sec having a peak at 00 nm. Band + S''' Stand ■. (V) U-B 1x2500 modified machine (Konica (made by barrel)), photoreceptor inflow current 200 μA, no exposure conditions,
Surface potential just before development measured with a 360SX electrometer (manufactured by Trenk). Half-reduced light, El/2 (#ux-sec) Using the above device, sharply cut the long wavelength component of 620 nm or more of the image exposure wavelength using dichroi and Kumirror (manufactured by Koshinko Co., Ltd.), and reduce the surface potential from 500 V. The amount of exposure required to reduce the voltage by half to 250V. (The exposure amount was measured using a 550-1 light meter (manufactured by EG and G).
Table 3 However, among the data in the table below, the left side (*1) is the data for the function-separated photoreceptor based on the present invention, and the right side (*2) is the data for the single-layer photoreceptor below. show. *1) Support: A1, blocking layer: 1 μm thick boron-doped a-3iC: H3 charge transport layer: 12 μm thick boron-doped A-3
iC: H3 charge generation N: 7 μm thick boron doped a
-3i nide ■, surface modified layer: 0.3 μm thick a-3i
CO:H *2) Support: Aβ, blocking layer: 1 μm thick boron-doped a-3iC: H1 photoconductive layer: 19 μm thick boron-doped a
SI: H% Surface modified layer: a-3iCO with a thickness of 0.3 μm
:H

[Brief explanation of the drawing]

1 to 2 show embodiments of the present invention, Figure 1 is a cross-sectional view of an a-5i photoreceptor; Figure 2 is a schematic cross-sectional view of the glow discharge device. It is. In addition, in the symbols shown in the drawings, 39...a-3i type photoreceptor 41...Support substrate) 42...Charge transport layer 43...Charge generation layer 44...Charge blocking layer 45...Surface modified layer It is. Agent Patent Attorney Sue Aisaka Younger brother 1 picture.

Claims (1)

[Scope of Claims] 1. A charge generation layer made of amorphous hydrogenated and/or halogenated silicon, a charge transport layer made of amorphous hydrogenated and/or halogenated silicon carbide, and the charge generation layer or charge transport layer an amorphous hydrogenated and/or halogenated amorphous material having a surface modified layer deposited on the surface of the amorphous hydrogenated and/or halogenated surface modified layer containing carbon atoms and oxygen atoms and also containing impurity elements of Group IIIA of the periodic table. It consists of silicon, and the amount of oxygen atoms is 1 to 20 atm% (however, the total amount of silicon atoms, carbon atoms, and oxygen atoms is 100 atm%).
Let it be m%. ), and the impurity element is 10^-^3 when forming the surface modified layer by glow discharge decomposition.
A photoreceptor in which the surface modification layer is doped under the following condition: Capacity ppm≦[Compound of impurity element]/[Silicon compound]≦10^3 Capacity ppm.