Evidence for charge gain mechanism in SI-GaAs detectors with epitaxial junction

Author

Bertolucci, E. ; Cola, A. ; Conti, M. ; De Luca, A. ; Mettivier, G. ; Russo, P. ; Quaranta, F. ; Vasanelli, L.

Author_Institution

Dipt. di Sci. Fisiche, Naples Univ., Italy

Volume

47

Issue

3

fYear

2000

fDate

6/1/2000 12:00:00 AM

Firstpage

780

Lastpage

783

Abstract

We made a characterisation of GaAs detectors with an epitaxial p-type layer deposited on the 200 μm semi-insulating substrate. The charge collection efficiency for 60-keV photons and 5.49 MeV alpha particle depends on the doping level of the p-layer. When completely depleted (reverse bias>200-300 V), the collected charge can be greater than 100%, implying the presence of some charge gain mechanism. At the same reverse bias and doping concentration, the collected charge depends also on the size of the contact pad. Moreover, the lower the p-doping, the lower the current density. The present findings confirm our previous work, obtaining gains up to 4:1

Keywords

X-ray detection; alpha-particle detection; gallium arsenide; semiconductor counters; semiconductor epitaxial layers; 200 to 300 V; 5.49 MeV; 60 keV; GaAs; charge collection efficiency; charge gain mechanism; contact pad; doping concentration; epitaxial junction; epitaxial p-type layer; p-layer; reverse bias; semi-insulating GaAs detectors; semi-insulating substrate; Alpha particles; Current density; Detectors; Doping; Gallium arsenide; Gold; Schottky barriers; Schottky diodes; Spectroscopy; Substrates;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/23.856515

Filename

856515