Electron diffusion length and lifetime in p -type GaN

Abstract

We report on electron beam induced current and current–voltage $\mathrm{(I–V)}$ measurements on Schottky diodes on p-type doped GaN layers grown by metal organic chemical vapor deposition. A Schottky barrier height of $\text{0.9\hspace{0.05em}}\mathrm{eV}$ was measured for the Ti/Au Schottky contact from the $\mathrm{I–V}$ data. A minority carrier diffusion length for electrons of $\text{(0.2±0.05)\hspace{0.05em}}\mathrm{\mu m}$ was measured for the first time in GaN. This diffusion length corresponds to an electron lifetime of approximately 0.1 ns. We attempted to correlate the measured electron diffusion length and lifetime with several possible recombination mechanisms in GaN and establish connection with electronic and structural properties of GaN.