Performance optimization of AlGaN-based LEDs by use of ultraviolet-transparent indium tin oxide: Effect of in situ contact treatment

Abstract

Ultraviolet (UV)-transparent indium tin oxide (ITO) grown by metal-organic chemical vapor deposition (MOCVD) is used as the current-spreading layer for 368 nm AlGaN-based light-emitting diodes (LEDs). By performing in situ contact treatment on the LED/ITO interface, the morphology, resistivity, and contact resistance of electrodes become controllable. Resistivity of 2.64 ' 10 %4 Ω cm and transmittance at 368 nm of 95.9% are realized for an ITO thin film grown with Sn-purge in situ treatment. Therefore, the high-power operating voltage decreases from 3.94 V (without treatment) to 3.83 V (with treatment). The improved performance is attributed to the lowering of the tunneling barrier at the LED/ITO interface.

Realization of p-GaN ohmic contact by using a strained p-AlInGaN interlayer and its application in UVA LEDs

“…ITO is a commonly used transparent conducting oxide which has a low resistivity and has very high transmittance in the visible and near-UV range. 5) Unfortunately, ITO has a low work function (4.8 eV); 6) when it is in contact with p-GaN, there is a large Schottky barrier height (SBH) of ∼2.7 eV. 7) To improve the electrical properties of ITO/p-GaN contact, researchers have made many attempts, such as using strained p + -InGaN and n + -InGaN capping layers, [7][8][9][10] and Ni-based interlayers.…”

Metal-modulated epitaxy of Mg-doped Al0.80In0.20N-based layer for application as the electron blocking layer in deep ultraviolet light-emitting diodes

“…High-resolution measurements uncovered signals at 73.9, 444.5, and 396.7 eV, which correspond to Al, In, and N, respectively. Specifically, the photoelectron signal at 73.9 eV is well-recognized as Al2p [40] , and the signal at 444.5 eV is associated with In3d in InN [41,42] . The N1s peak at a binding energy of 396.7 eV pertains to In−N bonds [43,44] .…”