Well width dependent luminescence characteristics of UV-violet emitting GaInN QW LED structures

Temperature and excitation power dependent photoluminescence spectroscopy on GaInN UV-violet LED structures allows to separate the influence of the quantum confined stark effect (QCSE) from carrier localization in In-induced band tail states as well as to determine the internal quantum efficiency (IQE). A LED series with different quantum well widths (1-3.7 nm) was grown by MOVPE on sapphire and low defect density (LDD) GaN templates. The photoluminescence data reveal, that the QCSE cannot be neglected even for low In-content (<10%) ultra violet LED structures. From temperature and laser power density dependent photoluminescence, the internal QE is evaluated. The data shows, that upon growth on LDD substrates, the internal QE is considerably increased for short wavelength (375-400 nm) LEDs.