Dependence of spectral behavior in an InGaN/GaN quantum-well light-emitting diode on the prestrained barrier thickness

The dependencies of output spectral overall redshift and current-density-induced spectral blueshift on the prestrained barrier thickness in the InGaN/GaN quantum-well light-emitting diodes (LEDs) of prestrained growth are demonstrated. Due to the stronger prestrain effect in a sample of a thinner prestrained barrier, the overall spectral redshift range increases and the current-density-induced blueshift range decreases with decreasing prestrained barrier thickness. Also, in terms of device resistance and saturation current, the LED performances of prestrained samples are superior to that of a conventional LED. With a thinner prestrained barrier, the device performance becomes better. The results are attributed to the higher average-indium content and stronger indium-rich clustering behavior in a sample of stronger prestrain. Such attributions are supported by the observations of strain state analysis in transmission electron microscopy measurements.