Measurement of piezoelectric field and tunneling times in strongly biased InGaN/GaN quantum wells

Abstract

We have measured both spectrum- and time-resolved photoluminescence (PL) of InGaN/GaN light-emitting diode structure as a function of an external bias. From spectrum-resolved PL, we observed regions of blueshift and redshift in peak PL energies. From the bias point at which redshift begins, which we attribute to the inversion of electric field due to full compensation of the piezoelectric field (PEF), we estimate PEF to be 2.1+/-0.2 MV/cm. From time-resolved PL, we found the carrier lifetimes to drastically decrease (2.5 ns-2 ps) with increasing reverse bias. We attribute this decrease to escape tunneling through tilted barriers.