Abstract

An all-solid-state, microscope-based time-resolved photoluminescence (TRPL) system has been developed for studying excess carrier dynamics, from the picosecond to the microsecond time domains, in III-V and n-VI semiconductor structures. The system employs laser diode excitation sources and a silicon single photon avalanche diode detector, and it allows TRPL measurements in the spectral region from 430 nm to ~1 μm. By using a 780 nm excitation source, the high spatial resolution of the system (<3 μm) has facilitated the examination of GaAs/AlGaAs MQW microresonator structures fabricated by alloy mixing techniques. These structures have important applications as surface-emitting lasers and as all-optical non-linear devices based on electronic band-filling nonlinearities. For each of these, a knowledge of carrier lifetime is of fundamental importance. Effective lateral carrier confinement is demonstrated in individual square pixels of various sizes, between 2 and 50 μm, with no significant reduction in carrier lifetime. The increasing importance of "wide-gap" II-VI semiconductors for the fabrication of blue light emitting diodes and laser diodes has led to the requirement for routine TRPL measurements on these materials. The integration of a frequency-doubled laser diode source, emitting at 420 nm, has permitted TRPL measurements to be performed on both n-and p-type ZnSe of various doping densities.

© 1992 Optical Society of America