Photocurrent mapping as a probe of transport properties and electric field distributions in cadmium zinc telluride detectors

Author

Toney, J.E. ; Brunett, B.A. ; Schlesinger, T.E. ; James, R.B.

Author_Institution

Dept. of Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA

Volume

44

Issue

4

fYear

1997

fDate

8/1/1997 12:00:00 AM

Firstpage

1684

Lastpage

1691

Abstract

We have performed two-dimensional cross-sectional photocurrent mapping of Cd_0.9Zn_0.1Te detectors grown by the high-pressure Bridgman method as a means of probing the electric field distribution. We have analyzed the results using a model based on the drift-diffusion equation. In the case of a uniform electric field and excitation far from the electrodes, the result is virtually identical in form to the Hecht relation. We adapt the Hecht relation to analyze photocurrent data and generalize it to the case of a nonuniform electric field. The spatial distribution of photocurrent for the material that we have examined suggests a nonuniformity in either the electric field or the electron mobility-lifetime product. These observations may help to explain the slope changes observed in detector response pulses

Keywords

cadmium compounds; crystal growth from melt; photoconductivity; semiconductor counters; semiconductor device models; zinc compounds; Cd_0.9Zn_0.1Te; Cd_0.9Zn_0.1Te detectors; Hecht relation; cadmium zinc telluride detectors; detector response pulses; drift-diffusion equation; electric field distributions; electron mobility-lifetime product; high-pressure Bridgman method; photocurrent mapping; transport properties; Data analysis; Detectors; Electrodes; Electron mobility; Equations; Nonuniform electric fields; Photoconductivity; Probes; Tellurium; Zinc;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/23.604133

Filename

604133