Piezoelectric effects in the optical properties of strained InGaN quantum wells

We investigated the carrier-injection effects in the emission spectrum of s trained GaN/InGaN/AlGaN quantum well (QW) blue emitters using a pulsed curr ent excitation technique. Spectral blueshift as large as 80 meV in the emis sion peak energy was observed as the injection current increases from 1 mA to 1 A. Based on a self-consistent calculation that couples the Poisson equ ation with a wurtzite-type Rashba-Sheka-Pikus Hamiltonian, four important i nteractions are evaluated in order to determine the optical properties of I nGaN QW. It is shown that the spectral redshifting caused by a piezoelectri city induced quantum confined Stark effect and carrier-induced band gap ren ormalization is counteracted by a blueshift due to the band filling and cha rge screening effects. The increase of InGaN QW emission peak energy and in tensity with injected carriers suggests a dominant contribution from the la tter in a band-to-band recombination process. (C) 1999 American Institute o f Physics. [S0003-6951(99)01906-3].