GaN-Based LEDs With Al-Doped ZnO Transparent Conductive Layer Grown by Metal Organic Chemical Vapor Deposition: Ultralow Forward Voltage and Highly Uniformity

In this letter, InGaN/GaN multiquantum well LEDs were fabricated with aluminum-doped zinc oxide (AZO) transparent conductive layer (TCL) grown by metal organic chemical vapor deposition (MOCVD) on n⁺-InGaN contact layer. Ultralow forward voltage (V_f) of 2.86 V at 20 mA was obtained, attributing to the epitaxial-like excellent interface between AZO/n⁺-InGaN contact layer confirmed by high-resolution transmission electron microscopy. The most worthy is that the V_f uniformity can be demonstrated on a 2-in wafer with a standard deviation of 0.02 V. Combined with the excellent light extraction, the MOCVD grown AZO-TCL is expected to be an alternative of tin-doped indium oxide in GaN-based LEDs for mass production.