Abstract:

A light-beam-generated space-charge inhomogeneity was used for the first time as a probing tool to study the behavior of deep levels in high-resistivity, Cr- doped GaAs using acoustic transient spectroscopy. The space-charge inhomogenity produced by the illumination of photoresistive piezoelectric semiconductors in a high-frequency electric field can generate, in proper conditions, both the surface and transversal or longitudinal acoustic wave. The temperature dependence of the time development of such a generated surface acoustic wave (SAW) after illumination by pulsed monochromatic light was used to investigate deep levels in high-resistivity GaAs using the technique of acoustic deep-level transient spectroscopy (A-DLTS) [P. Bury and I. Jamnicky, Proc. World Congress on Ultrasonics, Berlin, 1995, p. 535]. Deep-level parameters such as activation energy and capture cross-section were determined. [Work supported by a Grant of the Slovak Ministry of Education, No 1/1310/96.]