Low-temperature study of current and electroluminescence in InGaN/AlGaN/GaN double-heterostructure blue light-emitting diodes

Electrical and optical properties of Nichia double-heterostructure blue light-emitting diodes, with In0.06Ga0.94N:Zn, Si active layer, are investigated over a wide temperature range from 10 to 300 K. Current–voltage characteristics have complex character and suggest the involvement of various tunneling mechanisms. At small voltages (and currents), the peak wavelength of the optical emission shifts with the applied bias across a large spectral range from 539 nm (2.3 eV) up to 443 nm (2.8 eV). Light emission takes place even at the lowest temperatures, indicating that a complete carrier freeze-out does not occur.