A study on wavelength stability of GaN-based blue light emitting diodes

Although GaN-based blue and green light-emitting diodes (LEDs) have already been commercialized, the variation of the electro-luminescence wavelength of the LEDs along with the injection cur-rent remains a major problem. Furthermore, the full width at half maximum (FWHM) of the emission spectrum of the LEDs is relatively broad (typically greater than 25 nm). In this paper, high performance LEDs with InGaN/GaN multiple quantum wells were grown and fabricated by optimizing the growth conditions and the total strain in the structure. The emitting wavelength of our LEDs remains stable within 1 nm as the forward current varies from 0 to 120 mA. At a forward current of 20 mA, the FWHM of the emission spectrum is as low as 18 nm and remains basically constant as the forward current varies.