Abstract
We have studied the optical properties of InGaN/GaN quantum well (QW) structures with various barrier widths by means of cw and pulsed photoluminescence (PL) spectroscopy. With increasing barrier width, the cw PL peak energies of the InGaN/GaN QW samples shift to lower energy due to an enhancement of the quantum-confined Stark effect (QCSE) induced by the spontaneous and piezoelectric field effects. The calculated lowest quantized energies of the QW, $E_{n = 1}$ without an electric field and $E^{F}_{n = 1}$ with an electric field, agree well with the pulsed and cw PL peak energies, respectively. These results indicate that the PL spectra are strongly affected by the QCSE, which is induced by the spontaneous and piezoelectric fields in QW, samples and which increase with increasing barrier width.