The effect of Te dopant on the optical and electrical properties of high-resistivity AlSb crystals

Aluminum antimonide (AlSb) has a great potential application in electronic devices used at high temperatures. However, the properties of available AlSb crystals were still far away from the theoretical ones due to the high density of variant defects, especially point defects. Here, an improvement in optical transmittance and resistivity of AlSb was achieved by doping the as-grown AlSb with appropriate content of Te, through which the absorption of a spin split-off-heavy-hole band transition near 1.65 μm disappeared and the resistivity was increased from 102 to 106 ω cm. It was suggested that the residual acceptors with the binding energy EA of 37.4 meV were compensated by a Te donor with ED = 71 meV in the AlSb:Te crystal, according to the evaluation of the competing recombination (e, A0) and (Te0, A0). An energy band model was proposed to describe the recombination process and the underlying mechanism. The photo-response of the high resistance AlSb:Te crystal, illuminated by a pulsed LED light in the visible light range, revealed that the ratio of photocurrent to dark current was 128, indicating a great potential application for room-temperature photo-detection.