Photoconductivity in Vacuum Coated Selenium Films*

Keck, P. H.

doi:10.1364/josa.42.000221

Cited by 42 publications

(12 citation statements)

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“…At higher energies photoconduction sets in but its absolute value is still small [17,181. This behaviour indicates that the optical transition which creates the electroreflectance signal takes place into energy states where the carriers do not contribute to conduction.…”

Section: Discussionmentioning

confidence: 99%

Electroreflection of Amorphous Selenium

Weiser

Stuke

1969

Physica Status Solidi (b)

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. ing. GOBRECHT zum 60. Geburtstag gewidmet On amorphous selenium layers electroreflectance has been measured in the energy range from 1.7 to 4.2 eV. Only one relatively broad structure was found near 2.1 eV, i.e. below the electrical band gap and the photoconduction edge. It has a temperature coefficient of about -2.7 x eV/OK. The explanation of this structure by a Frenkel type exciton seems to be the most plausible.$n amorphen Selen-Schichten wurde das Elektroreflexions-Spektrum im Energiebereich von 1,7 bis 4,2 eV untersucht. Dabei wurde nur eine einzige, relativ breite Struktur bei 2,l eV gefunden, die unterhalb des elektrischen Bandabstandes und der Photoleitungskante liegt. Fur den Temperaturkoeffizienten ergab sich ein Wert von -2,7 x eV/"K. Als wahrscheinlichste ErklLrung fur die beobachtete Struktur wird ein Frenkel-Exziton angesehen.

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Section: Discussionmentioning

confidence: 99%

Electroreflection of Amorphous Selenium

Weiser

Stuke

1969

Physica Status Solidi (b)

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“…In the case of one group of lines observed in a single crystal, the envelope observed when the crystal was crushed, was compared with the spectra of silica, and a reasonable correspondence of the envelopes was found. 7 A similar calculation for the E/ center is described below. 5 The eigenvalues of the g tensor have been found.…”

Section: Introductionmentioning

confidence: 99%

Irradiation Effects and Short-Range Order in Fused Silica and Quartz

Weeks

Nelson

1960

Journal of Applied Physics

104

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An effect of antiphase boundaries on the kinetics of shortrange ordering by a vacancy mechanism J. Chem. Phys. 88, 3227 (1988); 10.1063/1.453917Effect of thermal relaxation and lowtemperature irradiation on the chemical shortrange order of amorphous ZrFe alloysThe eigenvalues of the g tensor of an irradiation produced defect of the quartz structure have been found to be gl =2.0003, g2=2.0006, g,=2.0018. The data on the center are consistent with the assignment of S=!.Assuming that the hyperfine interaction with Si 29 (I=! and 4.7% abundant) is negligible, the envelope of the line is calculated for 4 widths of the line. Good agreement is found between the calculated envelope for a width of 0.2 oe and the envelope observed in 'Y-ray and in neutron-irradiated (~10 18 fast neutrons/cm') silica. The observed envelope deviates from the calculated envelope for increasing neutron irradiation. It is suggested that a correlation of the Si-O tetrahedra, similar to a-quartz, exists around any point in the more common forms of silicas and has a diameter of 25 A.

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“…All discussions for the June 1977 Discussion Section should be submitted by Feb. 1, 1977. lamellae into the parent ~ phase (1,2). All discussions for the June 1977 Discussion Section should be submitted by Feb. 1, 1977. lamellae into the parent ~ phase (1,2).…”

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confidence: 99%

“…1. Internal oxidation (or sulfidation) has long been k n o w n (7) and the kinetics have been described in detail by Wagner (8) on the supposition that step [1] is rate controlling. The outer scale was found to be Ni sulfide plus Mo sulfide; the inner layer was Mo sulfide (dark region) plus nearly pure Ni metal (white region).…”

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confidence: 99%

“…The outer scale was found to be Ni sulfide plus Mo sulfide; the inner layer was Mo sulfide (dark region) plus nearly pure Ni metal (white region). Wagner's theory supposes that step [1] is controlled by inward diffusion of the oxidizing species through the depleted matrix, d, to reach the as yet unreacted alloy and, therefore, that both the penetration depth of the precipitation zone and the weight gain follow parabolic kinetics. The formation of the i n n e r layer is described in chemical terms as internal sulfidation.…”

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confidence: 99%

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Electrophotographic Characteristics of (HgI2 : CdS) Binder Layers

Pillai

Agarwal

Ahuja

1976

J. Electrochem. Soc.

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The combination of a photoconductor and insulating resin provides a photoconductive insulator capable of retaining a surface charge in d a r k and discharging in light. These combinations have some unique aspects: (i) The photoconductive material need not have high d a r k resistivity (which is required to retain charge) and this allows for a wide choice of materials. (ii) The independent characteristics of several photoconductors can be incorporated in one layer by dispersing these as powders in the resin binder. Several studies have been reported on the b i n d e r -t y p e plates of Se (1), ZnO (2), anthracene (3), CdS (4), and their combinations (5-6).The present investigations deal with the surface charge characteristics of HgI2:CdS mixed system in polystyrene. Our earlier photoconductivity studies (6) have shown that the binder layers of CdS dispersed in polystyrene have Iphoto/Idark • 100 and a low speed of response, while the binder layers of HgI2 have /photo/ /dark : 150 and a fast speed of response. This suggested that the binder layers of HgI2: CdS mixed system might possess some characteristics more desirable for use in electrophotography. T h e experiments have shown that the layer containing HgI2 and CdS in the 60:40 ratio exhibits the m a x i m u m value of Iphoto/Idark (5 X 103 at 1750 l x ) . It was then felt worthwhile to study the surface charge characteristics.The surface charge studies were made as follows: The photoconducting layers backed by NESA coated glass plates were charged by using a scorotron unit and the resulting surface charge was measured in terms of surface potential by a vibrating condenser unit. A 100W tungsten filament lamp was used to discharge the layers. Figure 1 shows typical dark and light decay curves of the HgI2, CdS, and HgI2: CdS layers. It is seen that (i) m a x i m u m surface potential is retained by the HgI2 layers, (ii) dark and light decay are fastest in HgI2 layers, and (iii) HgI2: CdS layers show slow dark and fast light decay rates.The effect of binder percentage on the d a r k and light decay rates of the HgI2:CdS layers is shown in Fig. 2. It is seen that as the percentage of binder is increased, the d a r k and light decay rates slow down, and that the surface potential retained b y the layer increases. F r o m these characteristics it is evident that the binder layers containing HgI2:CdS in the 60:40 composition dispersed in 60% by weight of polystyrene show the optimum characteristics for use in electrophotography. For this layer, the surface potential decays only by 5% in a period of 5 sec in dark, while during the same period the light decay is about 70% for 100 Ix white illumination. These values indicate that a good image contrast can be obtained, which could be further improved by exposing the layer to higher intensities of light. Fig. 1. Dark and light decay curves. Dark decay: (a) 100% Hgl2, (b) 60:40 Hgl2:CdS, (c) 100% CdS. Light decay: (1) 100% Hgl2, (2) 60:40 Hgl2:CdS, (3) 100% CdS. Binder percentage is 40 in all the samples.Fig. 2. Effect of ...

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Photoconductivity in Vacuum Coated Selenium Films*

Cited by 42 publications

References 2 publications

Electroreflection of Amorphous Selenium

Electroreflection of Amorphous Selenium

Irradiation Effects and Short-Range Order in Fused Silica and Quartz

Electrophotographic Characteristics of (HgI2 : CdS) Binder Layers

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