Interfacial modulation and plasmonic effect mediated high-brightness green light sources in a single Ga-doped ZnO microwire based heterojunction

Abstract

Heterostructure manufacturing has been extensively studied as an indispensable footstone in progressive semiconductor optoelectronic devices due to the constituent materials, interfacial states and electronic transport capabilities, thus enabling competitive candidates to construct novel devices and expand new academic fields. Herein, we proposed and constructed a unique green light-emitting diode (LED), which contains a Ga-doped ZnO microwire covered with Au nanoparticles (AuNPs@ZnO:Ga MW), a MgO buffer layer and a p-type InGaN template. The LED can exhibit high-brightness, highly-stable and nearly droop-free green light-emitting features. To probe into the electroluminescence mechanism, a band alignment modification at the ZnO:Ga/InGaN heterointerface can be fulfilled in the presence of a MgO buffer layer, which can effectively avoid the electron–hole recombination occurring at the InGaN side. Meanwhile capping AuNPs can availably achieve strengthening of the charge transport properties, enhancement of the forward current density of the diode, and magnification of the green light emission on the basis of the plasmonic effect. The carefully designed LED structures revealed much superior electroluminescence properties over a broad scope of carrier density because of the improvement of hole injection and electron confinement, thus moderately suppressing the efficiency droop induced by InGaN materials. This work provides clear grounds for the achievement of high-efficiency visible light sources and understanding the microscopic mechanism of reducing the electron leakage, increasing the hole injection efficiency and enhancing the electroluminescence efficiency.