Residual strain effects on the luminescence properties of self-organized GaN vertical nanorods grown by using HVPE

Abstract

The optical, structural, and vibrational properties of self-assembled GaN nanorods (NRs) were systematically examined to help understand the impact of residual strains on their emission properties. The GaN NRs grown at temperatures less than 550 A degrees C displayed line-defects along the a-axis, which are responsible for the residual compressive strain in the GaN NRs. The residual compressive strain, which depends on the growth temperature, gave rise to a blue-shift of the effective optical band-gap. Compared to the GaN thin films, the influence of residual strains on the blue-shift were more than 3-times greater for GaN NRs. This implies that growth interruptions to control the growth temperatures and/or source fluxes would be more critical in the fabrication of GaN-NR-based light-emitting devices.