Plasmon-enhanced high-performance Si-based light sources by incorporating alloyed Au and Ag nanorods

Abstract

Due to limitations of low-efficiency, indirect bandgap, large lattice mismatch with other semiconductors, and low carrier mobility, the development of efficient active region structures with nanostructured metals is of great technical significance for high-performance and high-efficiency Si-based low-dimensional light-emitting devices. In this work, single Ga-doped ZnO microwire (ZnO:Ga MW) was utilized to construct red light-emitting diodes (LED), with p-Si substrates acting as the hole source. When illuminated electrically, red-radiation was observed, with the lighting regions distributed along the body of the MW. With increasing forward current, the main emission wavelength peak stabilised at 680 nm. By incorporating alloyed Au and Ag nanorods (AuAgNRs) with desired plasmons, the red-emission of the single MW-based Si-LEDs was significantly enhanced. The influence of AuAgNR plasmons on the electroluminescence properties of the Si-based light source was further investigated. It was found that the emitted red light was absorbed by the AuAgNRs, leading to the excitation of localized surface plasmon resonances; in return, the AuAgNRs-plasmon can be employed to facilitate the recombination of the hole–electron confined in the depletion layer of the n-ZnO:Ga/p-Si interface, yielding the enhanced red-radiation. Benefiting from the deposited AuAgNRs with desired plasmons and excellent stability against various environments, the realization of plasmon-enhanced electrically-driven red light diodes provides a promising approach for the fabrication of high-efficiency Si-based light sources, as well as high-performance Si-based optoelectronics devices.