Structure and optoelectronic properties of single crystal epitaxial Cu(In1-xGax)Se2 and ordered defect compounds

Angus Rockett, G. Berry, D. Schroeder, H. Z. Xiao, L. Chung Yang

Research output: Contribution to journalConference articlepeer-review

Abstract

Epitaxial CuIn1-xGaxSe2 was grown on As-terminated (111) GaAs between 550 to 735°C with 0≤x≤1. The Cu/[In+Ga] ratio, y, ranged from y=0.3 to 1.3. Analysis of the deposited films showed an ordered defect structure that was homogeneous throughout the epitaxial layers when group III rich for all Ga contents examined. Films grown with y=0.3 had energy gaps of approx.1.2 eV and showed evidence by both cathodoluminescence and optical absorption of band tails. Stacking faults affect both the growth rate and the luminescence but can be converted to dislocations by rapid thermal annealing. The highest hole mobilities to date, > 1500 cm2 /V-sec, were measured at 50-75K by Hall-effect in near-stoichiometry samples. Room temperature hole mobilities were >200 cm2/V-sec and increased at low temperatures. Hole concentrations showed evidence of a level 80 meV above the valence band edge at a concentration in excess of 1017 cm-3 in all p-type samples. A composition-dependent level at approx.40 meV and type conversion at approx.100K was also observed.

Original languageEnglish (US)
Pages (from-to)172-175
Number of pages4
JournalConference Record of the IEEE Photovoltaic Specialists Conference
Volume1
StatePublished - Dec 1 1994
EventProceedings of the 24th IEEE Photovoltaic Specialists Conference. Part 2 (of 2) - Waikoloa, HI, USA
Duration: Dec 5 1994Dec 9 1994

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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