Electrical and optical properties of InGaN/AlGaN double heterostructure blue light-emitting diodes

Electrical and optical properties of InGaN/AlGaN double heterostructure blu e light-emitting diodes were investigated. Measurement of the forward bias current-voltage behaviour of the device demonstrated a departure from the S hockley model of a p-n diode, and it was observed that the dominant mechani sm of carrier transport across the junction is associated with carrier tunn elling. Electroluminescence experiments indicated that there was a main emi ssion band around 2.80 eV and a relatively weaker peak at 3.2 eV. A signifi cant blueshift of the optical emission band was observed, which was consist ent with the tunnelling character of electrical characteristics. Furthermor e, the degradation in I - V characteristics and the low resistance ohmic sh ort of the device were observed.