The influence of Cu (acceptor) and Ga (donor) on the electrical and optical properties of Hg1-xCdxTe (x=0.2) layers was investigated. The layers were grown by liquid-phase epitaxy from Te-rich solutions and the dopants were intentionally introduced during the growth process. Doping efficiencies between 0.025 at a hole concentration of p=6×10 18 cm-3 and 0.15 at p=6×1017 cm-3 were found for Cu. The electron concentration in the as-grown Ga-doped layers saturated at n=2×1017 cm-3, but increased significantly to n=8×1018 cm-3 as a result of an annealing process. The doping efficiency was 0.02. The doping and electrical properties of the layers are explained by assuming incorporation of both electrically active and electrically inactive impurity atoms. The high free electron concentrations in the Ga-doped layers resulted in a strong Burstein-Moss shift [T. S. Moss, G. J. Burrell, and B. Ellis, in Semiconductor Optoelectronics (Butterworths, London, 1973), p. 42] of the absorption edge, and effects of plasma frequency. These effects are analyzed and discussed.
ASJC Scopus subject areas
- Physics and Astronomy (all)