Defect study of Zn-doped p-type gallium antimonide using positron lifetime spectroscopy -: art. no. 075201

Defects in p-type Zn-doped liquid-encapsulated Czochralski-grown GaSb were studied by the positron lifetime technique. The lifetime measurements were performed on the as-grown sample at temperature varying from 15 K to 297 K. A positron trapping center having a characteristic lifetime of 317 ps was identified as the neutral V-Ga-related defect. Its concentration in the as-grown sample was found to be in the range of 10(17)-10(18) cm(-3). At an annealing temperature of 300 degreesC, the V-Ga-related defect began annealing out and a new defect capable of trapping positrons was formed. This newly formed defect, having a lifetime value of 379 ps, is attributed to a vacancy-Zn-defect complex. This defect started annealing out at a temperature of 580 degreesC. A positron shallow trap having binding energy and concentration of 75 meV and 10(18) cm(-3), respectively, was also observed in the as-grown sample. This shallow trap is attributed to positrons forming hydrogenlike Rydberg states with the ionized dopant acceptor Zn.