The influence of driving current on emission spectra of GaN-based LED

The InGaN/GaN multiple quantum wells (MQWs) light emitting diodes (LEDs) were grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrates. The emission spetrum, chromaticity coordinates of the GaN-based blue LED have been measured under varied driving current. The results indicated that as the driving current increases from 1 mA to 20 mA, the peak wavelength of EL spetrum has slightly shifted toward short-wavelength (blue-shift) due to radiation recombination of the donor-acceptor pairs localized energy state in the InGaN well layer, the x value increases, but the y value decreases. When continuatively increasing forward current, a slowly red-shift of the emitting peak wavelength has been observed due to the temperature dependence of band-gap energy, the x value decreases, but the y value increases. The FWHM of EL spetrum increases as the driving current increases.