Single microwire based smart color-switchable light-emitting diode

Abstract

Achieving high-brightness and high-efficiency low-dimensional light sources remains a challenging issue due to the lack of high electrical conductance electrodes, as well as the efficient charge injection into the luminescent layer. Herein, by employing chemical vapor deposition methods, individual ZnO microwires with heavily Ga-impurity (GZO MWs) have been successfully synthesized, and then directly assembled on p-GaN substrate to form a heterostructure light-emitting device. In the device, the single GZO MW, which possessing metallic behavior, can function as an outstanding conductance electrode, whilst an efficient luminescence layer. Electroluminescence (EL) characteristics of the single GZO MW-diode operated under forward bias were performed, yielding bright, blue/green lighting with the main peaks positioned at 450 nm and spectral line width of 90 nm. While it also can emit strong broadband, stable and monochromatic white emission under reverse bias. The dual-color-illuminating can be switched repeatedly by reversing the bias polarity. The bias-polarity-switched light source enables independent control over the EL illuminating-color and brightness. The fabrication of single MW based color-switchable light-emitting diode can afford a promising scheme toward the miniaturized, and smart light sources, which hold tremendous power in optical communication, optoelectronic devices and photoelectricity encoders.