Hole localization effect on determination of charge accumulation in double barrier resonant tunneling structures

We have investigated photoluminescence of double-barrier diodes under various bias voltages and observed the saturation of the broadening of the photoluminescence lines. We have also studied the integrated photoluminescence intensity with increasing applied voltages near resonant voltages for high quality samples at low temperature (4.2K). The results of the 77K photoluminescence experiments confirm those at 4.2K. The saturation of the broadening is due to weak hole localization; however, the saturation of the integrated photoluminescence intensity is mainly due to reduced nonradiative recombination. Our results suggest that the hole localization may arise from interface roughness.