InGaN/GaN double heterostructure and multiple quantum wells (MQW) light-emitting diodes were grown by metalorganic vapor phase epitaxy. Band gap narrowing of the PL spectra for the InGaN/GaN MQW LEDs can be observed at room temperature. In addition, the emission wavelength of EL and PL spectra for the MQW blue LEDs exhibit a blue-shift phenomenon when increasing the injection current and laser power, respectively. This luminescence behavior can tentatively be understood as a competition between a spectral red-shift mechanism of piezoelectrically-induced quantum-confined Stark effect and a blue-shift mechanism of band-filling and charge screening effects.
J. K. Sheu,
M. J. Jou,
"Luminescence of the InGaN/GaN blue light-emitting diodes", Proc. SPIE 4079, Display Technologies III, (30 June 2000); doi: 10.1117/12.389421; https://doi.org/10.1117/12.389421