Hydrogenated Amorphous Silicon / ZnO Shottky Heterojunction for Position Sensitive Detectors

ABSTRACTIn this work a new structure is proposed for position sensitive detectors consisting of glass/Cr/a-Si:H(n+)/a-Si:H(i)/ZnO, where the ZnO forms an heterojunction with the a-Si:H(i). The results show that this structure works with success in the fabrication of linear position sensitive detectors. The devices present a good nonlinearity of ͌ 2% and a good sensitivity tothe light intensity. The main advantages of this structure over the classical p-i-n are an easier to built topology and a higher yield due to a better immunity to the a-Si:H pinholes, since the ZnO does not diffuse so easily into a-Si:H as the metal does, which are the cause of frequent failure in the p-i-n devices due to short-circuits caused by the deposition of the metal over the a-Si:H. In this structure the illumination is made directly on the ZnO, so a transparent substrate is not needed and a larger range of substrates can be used.

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Position sensitive detectors using hydrogenated amorphous silicon

Journal of Physics D Applied Physics ◽

10.1088/0022-3727/21/2/018 ◽

1988 ◽

Vol 21 (2) ◽

pp. 359-363 ◽

Cited By ~ 7

Author(s):

S K Al Sabbagh ◽

J I B Wilson ◽

W Z Manookian

Keyword(s):

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Position Sensitive ◽

Position Sensitive Detectors ◽

Hydrogenated Amorphous

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Fast light-induced change in ellipsometry spectra of hydrogenated amorphous silicon measured through a transparent substrate upon bias light illumination

MRS Proceedings ◽

10.1557/proc-664-a19.5 ◽

2001 ◽

Vol 664 ◽

Cited By ~ 1

Author(s):

N. Hata ◽

C. M. Fortmann ◽

A. Matsuda

Keyword(s):

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Light Illumination ◽

Temperature Dependent ◽

Transparent Substrate ◽

Optical Effects ◽

The Stability ◽

Fast Light ◽

First Time ◽

Hydrogenated Amorphous

ABSTRACTPrevious ellipsometric studies of the stability of amorphous silicon (a-Si:H) found reversible changes in the pseudo-dielectric functions. These changes were slow to generate and slow to anneal away. These slow changes are associated with a dangling bond related structural change. Since any light-induced change in the dielectric function is useful for photonic engineering, we undertook the present more detailed study of light induced optical effects in a-Si:H. The optical pseudo-dielectric functions of hydrogenated amorphous silicon (a-Si:H) were measured using spectroscopic ellipsometry (SE) and the “through-the-substrate” measurement technique as a function of measurement temperature and bias light illumination. For the first time we report a light-induced change in a-Si:H materials that is fast, bias-light-dependent, reversible, and temperature dependent. This effect, while not completely understood, offers exciting new prospects for photonic engineering.

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Calibration of a 2 dimensional hydrogenated amorphous silicon thin film position sensitive detector (2D a-Si:H TFPSD)

The European Physical Journal Applied Physics ◽

10.1051/epjap:2003072 ◽

2003 ◽

Vol 24 (3) ◽

pp. 231-239

Author(s):

K. Gnanvo ◽

Z. Y. Wu

Keyword(s):

Thin Film ◽

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Position Sensitive Detector ◽

Sensitive Detector ◽

Silicon Thin Film ◽

Position Sensitive ◽

Hydrogenated Amorphous

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Kinetics of Growth and Recovery of Light-Induced Defects Under High-Intensity Illumination

MRS Proceedings ◽

10.1557/proc-258-473 ◽

1992 ◽

Vol 258 ◽

Cited By ~ 4

Author(s):

Masao Isomura ◽

Sigurd Wagner

Keyword(s):

Light Intensity ◽

Amorphous Silicon ◽

High Intensity ◽

Hydrogenated Amorphous Silicon ◽

Increased Sensitivity ◽

Induced Defects ◽

Hydrogenated Amorphous ◽

Kinetics Of ◽

Diffusion Of Hydrogen

ABSTRACTWe report a study of the rates of generation and of annealing of the light-induced defects in hydrogenated amorphous silicon (a-Si:H). The rates of generation are found to be sensitive to temperature when the light intensity is high. This increased sensitivity to temperature at high rates suggests that a temperature-activated process such as hydrogen motion controls the rates of generation more when they are high. The rate of annealing at 130°C is strongly accelerated by illumination, and depends strongly on the light intensity. This may be explained by the diffusion of hydrogen, accelerated by excess carriers.

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Toward a Practical Model of a-Si:H Defects in Intensity-Time-Temperature Space

MRS Proceedings ◽

10.1557/proc-336-165 ◽

1994 ◽

Vol 336 ◽

Cited By ~ 7

Author(s):

D. Caputo ◽

J. Bullock ◽

H. Gleskova ◽

S. Wagner

Keyword(s):

Light Intensity ◽

Fermi Level ◽

Amorphous Silicon ◽

Thermal Annealing ◽

Hydrogenated Amorphous Silicon ◽

Defect States ◽

Quasi Fermi Level ◽

Practical Model ◽

Density Of Defect States ◽

Hydrogenated Amorphous

ABSTRACTIn this paper we develop a model of the defect kinetics in hydrogenated Amorphous silicon (a:Si:H) with the goal of predicting the density of defect states g (E) established by any given light intensity I, for arbitrary times t and temperatures T. While we build on widely accepted expressions for the the rates of light-induced and thermal annealing, we examine in more detail the light induced annealing (LIA) term. The model shows that the LIA process can be described with the thermal annealing term if a suitable reduction to the annealing energy is introduced. This reduction depends on the light intensity such as to suggest a relation to the shift of the electron quasi-Fermi level under illumination.

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Reduction of Si-H2 Bond Content in Hydrogenated Amorphous Silicon Prepared by Mercury-Sensitized Photochemical Vapor Deposition

MRS Proceedings ◽

10.1557/proc-192-517 ◽

1990 ◽

Vol 192 ◽

Cited By ~ 1

Author(s):

N. Sakuma ◽

H. Nozaki ◽

T. Niiyama ◽

H. Ito

Keyword(s):

Light Intensity ◽

Amorphous Silicon ◽

Hydrogen Content ◽

Vapor Deposition ◽

Hydrogenated Amorphous Silicon ◽

Silicon Films ◽

The Other ◽

Photochemical Vapor Deposition ◽

Hydrogenated Amorphous ◽

Deposition Conditions

ABSTRACTThe ratio of Si-H2 bonds to hydrogen content in hydrogenated amorphous silicon films, prepared by mercury-sensitized photochemical vapor deposition, depends on the deposition conditions, in particular on the distance between the substrate and the light-transparent window.The ratio is reduced from 20 % to 8 % by decreasing the distance from 30 mm to 8 mm. On the other hand, the hydrogen content remains constant at 15 at.%. Decreasing the distance has been found to be almost equivalent to increasing the light intensity, especially 254 nm-light intensity.

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Position‐sensitive photodetector based on hydrogenated amorphous silicon p‐i‐n junctions

Review of Scientific Instruments ◽

10.1063/1.1139307 ◽

1987 ◽

Vol 58 (2) ◽

pp. 202-206 ◽

Cited By ~ 2

Author(s):

V. A. Chumak ◽

M. Bertolotti ◽

A. Ferrari ◽

F. Bartoloni ◽

F. Evangelisti

Keyword(s):

Amorphous Silicon ◽

Hydrogenated Amorphous Silicon ◽

Position Sensitive ◽

Hydrogenated Amorphous

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Changes of Drift Mobility in a-Si:H with Light Exposure and Doping

MRS Proceedings ◽

10.1557/proc-95-571 ◽

1987 ◽

Vol 95 ◽

Cited By ~ 2

Author(s):

J. Takada ◽

H. Fritzsche

Keyword(s):

Light Intensity ◽

Amorphous Silicon ◽

Light Exposure ◽

Hydrogenated Amorphous Silicon ◽

Drift Mobility ◽

Mobility Edge ◽

Strong Light ◽

Quasi Fermi Level ◽

Multiple Trapping ◽

Hydrogenated Amorphous

AbstractMeasurements of the drift mobility μ of photo-excited electrons in n-type hydrogenated amorphous silicon (a-Si:H) as a function of light intensity are reported. The value of μ increases as the quasi Fermi level is moved closer to the transport states in accordance with the multiple trapping theory. The drift mobility decreases with increasing doping as well as with an increase in the concentration of metastable dangling bonds defects by strong light exposures. This decrease in μ between 300 and 360K can be explained by a corresponding decrease in the microscopic mobility, by an increase in the density of tail states within 0.35eV below the electron mobility edge, or by a combination of both these effects.

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