Transition selective PL in InAs by using frequency-domain measurements

This study explores the transition-selective photoluminescence (PL) of InAs by analyzing the excitation frequency and detection-phase angle dependence of PL measurements. Each PL transition had a unique lifetime, resulting in a unique phase delay when subjected to sinusoidal excitation. The transition selection leverages the unique phase delay for PL transition. The PL lifetimes of InAs were calculated to determine the optimal excitation frequency. At lower excitation frequencies, transition selectivity was not achieved as the phases of the transitions all aligned at 0. However, as the excitation frequency increased, the PL emission at lower energies diminished, resulting in a blue shift in PL spectra. This shift was attributed to impurity-related PLs with slower lifetimes compared with the interband-related PLs. Successful transition selection was achieved under specific conditions of excitation frequency and phase angle. In addition to the impurity-related PL transitions in InAs, two band-to-band transitions were identified, and their origins were speculated.