Transport imaging for contact-free measurements of minority carrier diffusion in GaN, GaN/AIGaN, and GaN/lnGaN core-shell nanowires

摘要

Minority carrier diffusion lengths (L_d) are measured for GaN, GaN/AIGaN, and GaN/lnGaN core-shell nanowires using a technique based on imaging of recombination luminescence. The effect of shell material on transport properties is measured. An AlGaN shell produces L_d values in excess of 1 μm and a relative insensitivity to wire diameter. An InGaN shell reduces effective diffusion length, while a dependence of Lj on diameter is observed for uncoated nanowires.