Physico-Chemical Origin of Majority and Minority Carrier Traps in N-Type VPE and LPE GaAs

Abstract

Schottky barrier capacitance techniques are used to characterize the deep-lying electron and hole trapping centres in the forbidden energy gap of n-type GaAs grown by VPE and LPE techniques. The activation energy, capture cross-section and the density of these centres are determined. It is shown that an electron trap at 0.70 eV below the lowest energy conduction band minimum and a hole trap at 0·64 eV above the valence band maximum are present in VPE and LPE GaAs, respectively. These trapping centres are associated with Ga vacancies in VPE GaAs and As vacancies in LPE GaAs.

Indexing Terms:

• GaAs
• Electron & Hole Traps
• As & Ga Vacancies
• III-V compounds

Additional information

Notes on contributors

Ashok K. Saxena

Saxena, Ashok K (Dr): (b. 1950). Obtained MSc in Physics and MSc (Tech) in Electronics in 1969 and 1971 from Agra university and BITS, Pilani respectively. In 1974, joined the University of Sheffield, UK and was awarded M. Eng. and PhD in Solid State Electronics in 1975 and 1978 respectively. From 1971 to 1974, he was with CEERI, Pilani and was responsible for the design and development of Si avalanche diodes and oscillators. He also attended a course on Solid State Electronics at the Institute of Sc. and Tech., University of Manchester and worked with Standard Telecommunication Laboratory, Harlow. IETE honoured him with S.K. Mitra Memorial Award in 1976 and I.N.S.A. with Young Scientist Award in 1980 for outstanding research work. His present interests are in the growth and electrical properties of III-V group binary and ternary semiconductor compounds. Presently, he is Reader in ECE Deptt of University of Roorkee.

Dr. Saxena is a member of IEEE, IETE and an associate member of Inst, of Phys. He has published nearly twenty papers in various international journals.