High-brightness Yellow Light-emitting Diode in A Single Ga-doped ZnO∶Ga Microwire Heterojunction

Due to low-dimensional semiconductor micro/nano-structures， visible light-emitting devices， especially for green/yellow light sources locating in the wavelengths of 500-600 nm， have reached a broad audience in ultrahigh resolution display and lighting， single-photon source， single-molecule sensing and imaging in life science and other fields. In developing high-performance green/yellow light-emitting devices， the preparation of light-emitting materials and device structures is highly restricted by the “green/yellow gap” and “efficiency droop”. In the present research， a new generation of yellow light-emitting diode， which is composed of a single Ga-doped ZnO microwire（ZnO∶Ga MW） and p-type InGaN substrate， is demonstrated at a wavelength of 580 nm together with a linewidth of about 50 nm. With increasing the drive current at high injection levels， hardly little variation in the spectral profiles， such as the main emission wavelengths and the linewidth， could be distinctly noticed， as well as the quantum Stark effect that has been normally observed in InGaN-based light sources. The color coordinate is well matched with the yellow of the REC.2020 standard. Interestingly， the external quantum efficiency of the device is relatively stable even at high current injection. By comparing with the photoluminescence properties of a ZnO∶Ga MW and p-InGaN film， the energy band structure of the as-fabricated n-ZnO∶Ga/p-InGaN heterojunction emission device was constructed. It is clearly inferred that the electroluminescence is derived from the generation of electron-hole recombination， which occurring close to the ZnO∶Ga/InGaN heterointerface， instead of the p-InGaN side. The experimental results show that the as-designed n-ZnO∶Ga MW/p-InGaN heterojunction can be used to fabricate high-performance low-dimensional yellow light-emitting diodes. © 2022 Chines Academy of Sciences. All rights reserved.