The mechanism of generation of donor centres in p-InSb by laser radiation

The laser-induced donor centers in p-InSb have been studied by magneto-conc entration effect (MCE). The distribution of In vacancies in a nonuniform te mperature field in InSb has been performed in term of the model of redistri bution of the In vacancies under laser action. Comparison of the theoretica l and experimental data has shown that the depth of the p-n junction increa ses with temperature and that the relatively large value of the p-n junctio n localization depth at intensities of laser radiation exceeding 3.5 MW cm( -2) is connected with presence of the liquid phase in the laser modificatio n process. These results are confirmed by atomic force microscopy (AFM) of the surface morphology. Experiments were performed on InSb samples in the t emperature range 180-290 K. Temperature gradient was provided by YAG:Nd las er illumination (lambda = 0.53 mu m, tau(p) =15 ns). Two kinds of laser don or centers (LDC) were found: one is nonstable, annealed at room temperature with relaxation constant similar to 5 s, and the other is stable, annealed at 670 K. The threshold of LDC formation is 1.5 MW cm(-2). The activation energy of the stable donor centre is similar to 1.1 eV. (C) 1999 Elsevier S cience B.V. All rights reserved.