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

Minority carrier diffusion lengths (L-d) are measured for GaN, GaN/AlGaN, and GaN/InGaN 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 mu m and a relative insensitivity to wire diameter. An InGaN shell reduces effective diffusion length, while a dependence of L-d on diameter is observed for uncoated nanowires. (C) 2011 American Institute of Physics. [doi:10.1063/1.3573832]