The Optical Properties of Dual-Wavelength InxGa1−xN/GaN Nanorods for Wide-Spectrum Light-Emitting Diodes

Abstract

We fabricated the dual-wavelength InxGa1−xN/GaN nanorods for wide-spectrum light-emitting diodes (LEDs) by silica nanosphere lithography (SNL) technique. The emission properties of the dual-wavelength nanorods are characterized by micro-photoluminescence (micro-PL), cathodoluminescence (CL), and temperature-dependent PL (TDPL) measurements. Nanorod structure can effectively suppress quantum confined Stark effect (QCSE) compared with planar structure due to the strain relaxation. In addition, the internal quantum efficiency (IQE) of the green quantum well (QW) within nanorod structure increases, but the IQE of the blue QW clearly decreases because blue QW has severely suffered from the nonradiative recombination by surface damage. Furthermore, the IQEs of the green QW and the blue QW within the nanorod structure can be effectively improved by wet etching treatment, with an increase in factor by 1.3 when compared with unetched nanorod structure. Evidently, the dual-wavelength InxGa1−xN/GaN nanorods are beneficial to improve the optical performance compared with planar structure, presenting a potential to realize monolithic, high-efficiency, and cost-effective white LEDs.