Optical and electrical studies of arsenic-implanted HgCdTe films grown with molecular beam epitaxy on GaAs and Si substrates

A defect study was performed on arsenic-implanted Hg1-xCdxTe (x = 0.23-0.30) films with graded-gap surface layers, grown with molecular-beam epitaxy on GaAs and Si substrates and designed for fabrication of 'p+-n'-type photodiodes. First, formation of n+-p structure was investigated in p-type material, in order to study radiation-induced donor defects. Next, formation of p+-n structure was investigated in the course of implantation in n-type material and arsenic activation annealing. Influence of the graded-gap surface layer was found to be expressed in the degree of saturation of the concentration of radiation-induced defects, with results obtained on arsenic- and boron-implanted material differing due to the difference in the ion masses.