Effects of defects on metal-insulator semiconductor properties of molecular-beam epitaxy grown HgCdTe

Abstract

We present results which show that physical defects in molecular-beam expitaxy grown HgCdTe strongly affect its metal-insulator semiconductor properties. In particular, two types of defects, dislocations and pyramidal hillocks, affect the dark and tunnel currents. However, when the dislocation densities are reduced to the same level (105 cm−2) found in material grown by other growth methods, the dark currents and hence storage times are comparable. For cutoff wavelengths of 9.8 μm we observe a storage time of 150 μs in one film. For films with high dislocation densities (107 cm−2) the predominate dark currents at high temperatures (T≥100 K) are generation–recombination dark currents, while for films with low dislocation densities near diffusionlike dark currents dominate.