Picosecond time-resolved luminescence studies of surface and bulk recombination processes in InP

Abstract

Recombination processes in InP have been studied using picosecond-time-resolved photoluminescence (PL). The technique makes it possible to measure the intrinsic surface recombination velocity (SRV) and the bulk lifetime \ensuremath{\tau} directly and independently. The results show that both p- and n-type InP(110) etched surfaces have similarly low SRV, contrary to commonly accepted values. Moreover, it is found that n-type InP is distinguished by a very long nonradiative lifetime ${\mathrm{\ensuremath{\tau}}}_{\mathrm{nr}}$ (320 ns) and the bulk recombination process is mainly radiative. On the other hand, the ${\mathrm{\ensuremath{\tau}}}_{\mathrm{nr}}$ of p-type InP is very small (\ensuremath{\le}33 ns), apparently due to a high concentration of deep traps, and nonradiative bulk recombination is dominant. These results are discussed in view of other measurements and models. The SRV of metal/InP interfaces shows a strong dependence on the reactivity of the metal-semiconductor anion pair, which resembles the dependence found for the Schottky-barrier height at these interfaces. These measurements are compared to results also obtained in this work for UHV-cleaved surfaces.