Dynamics of bound excitons versus thickness in freestanding GaN wafers grown by halide vapor phase epitaxy

作者：Pozina G^*; Hemmingsson C; Bergman J P; Trinh D; Hultman L; Monemar B

来源：Applied Physics Letters, 2007, 90(22): 221904.

DOI：10.1063/1.2743950

The bound exciton recombination properties in freestanding GaN layers of various thicknesses grown by halide vapor phase epitaxy have been characterized by time-resolved spectroscopy. Improvement of the donor bound exciton (D0X) lifetime was observed with increasing GaN layer thickness up to similar to 400 mu m, while for thicker layers the recombination time of D0X shows a tendency to saturate. The thickness-dependent behavior of the D0X decay can be understood in terms of competition between two nonradiative mechanisms: one of which is connected to structural defects, and consequently more important for thinner layers, while for layers with thickness above 400 mu m with low structural defect density the recombination time is limited by point defects such as impurities and vacancies.

• 出版日期2007-5-28