Study of optical properties of swift heavy ion irradiated gallium antimonide

Gallium antimonide (GaSb) which is a narrow band gap compound semiconductor has received attention because of its potential applications in optoelectronic devices. In the present work, p-type GaSb wafers of < 100 > orientation were irradiated with 70 MeV Fe-56 ions at fluences varying from 1 x 10(12) to 1 x 10(14) ions cm(-2). Mid-infrared and Far-infrared Fourier Transform (FT) measurements were carried out to investigate the optical properties of as irradiated and vacuum annealed samples. Mid-infrared Fourier Transform study revealed that the optical absorption of the irradiated samples increases with increasing ion fluence due to increase in irradiation-induced defects. The band gap energy determined from the infrared spectra was found to change from 0.65 to 0.62 eV while for non-irradiated GaSb wafer the corresponding estimate was 0.67 eV. The density of the carrier estimated from the plasma frequency (omega(p)) was found to vary from 2.05 x 10(18) to 1.9 x 10(18) cm(-3). The samples annealed in vacuum (10(-6) mb) over the temperature range 100-600 degrees C showed the significant damage recovery. Crown Copyright (c) 2005 Published by Elsevier B.V. All rights reserved.