GaN avalanche photodiodes grown on m-plane freestanding GaN substrate

摘要

M-plane GaN avalanche p-i-n photodiodes on low dislocation density freestanding m-plane GaN substrates were realized using metal-organic chemical vapor deposition. High quality homoepitaxial m-plane GaN layers were developed; the root-mean-square surface roughness was less than 1 A and the full-width-at-half-maximum value of the x-ray rocking curve for (1010) diffraction of m-plane GaN epilayer was 32 arcsec.High quality material led to a low reverse-bias dark current of 8.11 pA for 225 μm~2 mesa photodetectors prior to avalanche breakdown, with the maximum multiplication gain reaching about 8000.