Low current driven bidirectional violet light emitting diode based on p-GaN/n-InN heterojunction

Abstract

The fabrication of a low current bidirectional driven violet p-GaN/n-InN heterojunction light-emitting diode (LED) by the radio-frequency (RF) magnetron sputtering is reported in this paper. The indium nitride (InN) films grown at different substrate temperatures were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-2600 spectrophotometer and Hall test system, and the optimum substrate temperature was found to be 250 °C. The bidirectional electroluminescence (EL) behavior and the luminescence mechanism of the diode have been investigated. Based on the above, the bidirectional EL and the effect of ambient temperature (room temperature (RT) to 80 °C) on the luminescence properties of the diode have been investigated. The diode can be driven bidirectionally at very low currents (0.03 mA under forward and 0.01 mA under reverse) and produce high-brightness violet light at forward currents of 1–5 mA and reverse currents of 1–3 mA. Finally, the EL spectra were subjected to the Gaussian peak fitting process combined with energy band diagrams to analysis the luminescence mechanism of the diode. The EL spectra all show predominantly violet emission and interface defects emissions under different polarity current drive. The proposed bidirectional violet LED based on p-GaN/n-InN heterojunction will be a potential commodity for the bidirectional driven LED market in the future.