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Title: Role of deep level trapping on surface photovoltage of semi-insulating GaAs

Abstract

Dual beam (bias and probe) transient Surface Photovoltage (SPV) measurements were made on undoped Semi-Insulating (SI) GaAs over an extended temperature range. Above 270 K, SPV recovery transients following a bias pulse were shown to reflect near surface conductivity changes; these are in turn controlled by surface/interface state thermal emission. Owing to the absence of a strong surface electric field in this material, the emitted carriers are not immediately removed from the near surface region. The recapturing of the emitted carriers is shown to be responsible for non-exponential conductivity and reciprocal-SPV transients. This behavior is considered to be characteristic of relaxation-type semiconductors with near-surface ungated structures. Below 150 K, the photoinduced transition of EL2 from its ground to metastable state El2* was shown to change the effective electron and hole mobilities and augment the SPV signals immediately following the bias pulse. Thermally induced EL2* recovery above 120 K decreases the SPV signal from its maximum. This decay transient was analyzed and the decay rate fitted to a single exponential. An activation energy of 0.32 eV and a pre-exponential constant of 1.9 {times} 10{sup 12} s{sup {minus}1} were obtained, and attributed to the thermal recovery rate for EL2*.

Authors:
; ; ; ; ;  [1]
  1. Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science
Publication Date:
OSTI Identifier:
417727
Report Number(s):
CONF-960401-
ISBN 1-55899-329-0; TRN: IM9705%%100
Resource Type:
Book
Resource Relation:
Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 8-12 Apr 1996; Other Information: PBD: 1996; Related Information: Is Part Of Thin films for photovoltaic and related device applications; Ginley, D. [ed.] [National Renewable Energy Lab., Golden, CO (United States)]; Catalano, A. [ed.] [Technology Assessment Group, Boulder, CO (United States)]; Schock, H.W. [ed.] [Univ. Stuttgart (Germany)]; Eberspacher, C. [ed.] [Unisun, Newbury Park, CA (United States)]; Peterson, T.M. [ed.] [Electric Power Research Inst., Palo Alto, CA (United States)]; Wada, Takahiro [ed.] [Matsushita Electric Industries Co., Ltd., Kyoto (Japan)]; PB: 621 p.; Materials Research Society symposium proceedings, Volume 426
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GALLIUM ARSENIDES; PHOTOCONDUCTIVITY; ELECTRIC POTENTIAL; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K; CARRIER MOBILITY; ACTIVATION ENERGY; ELECTRICAL TRANSIENTS; TIME DEPENDENCE; EXPERIMENTAL DATA

Citation Formats

Liu, Q, Ruda, H E, Koutzarov, I P, Jedral, L, Chen, G, and Prasad, M. Role of deep level trapping on surface photovoltage of semi-insulating GaAs. United States: N. p., 1996. Web.
Liu, Q, Ruda, H E, Koutzarov, I P, Jedral, L, Chen, G, & Prasad, M. Role of deep level trapping on surface photovoltage of semi-insulating GaAs. United States.
Liu, Q, Ruda, H E, Koutzarov, I P, Jedral, L, Chen, G, and Prasad, M. Tue . "Role of deep level trapping on surface photovoltage of semi-insulating GaAs". United States.
@article{osti_417727,
title = {Role of deep level trapping on surface photovoltage of semi-insulating GaAs},
author = {Liu, Q and Ruda, H E and Koutzarov, I P and Jedral, L and Chen, G and Prasad, M},
abstractNote = {Dual beam (bias and probe) transient Surface Photovoltage (SPV) measurements were made on undoped Semi-Insulating (SI) GaAs over an extended temperature range. Above 270 K, SPV recovery transients following a bias pulse were shown to reflect near surface conductivity changes; these are in turn controlled by surface/interface state thermal emission. Owing to the absence of a strong surface electric field in this material, the emitted carriers are not immediately removed from the near surface region. The recapturing of the emitted carriers is shown to be responsible for non-exponential conductivity and reciprocal-SPV transients. This behavior is considered to be characteristic of relaxation-type semiconductors with near-surface ungated structures. Below 150 K, the photoinduced transition of EL2 from its ground to metastable state El2* was shown to change the effective electron and hole mobilities and augment the SPV signals immediately following the bias pulse. Thermally induced EL2* recovery above 120 K decreases the SPV signal from its maximum. This decay transient was analyzed and the decay rate fitted to a single exponential. An activation energy of 0.32 eV and a pre-exponential constant of 1.9 {times} 10{sup 12} s{sup {minus}1} were obtained, and attributed to the thermal recovery rate for EL2*.},
doi = {},
url = {https://www.osti.gov/biblio/417727}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {12}
}

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