Identification of Burgers vectors of threading dislocations in freestanding GaN substrates via multiphoton-excitation photoluminescence mapping

Abstract

Burgers vectors b of threading dislocations in freestanding GaN substrates were identified through statistical classification using the etch pit and multiphoton-excitation photoluminescence methods. The b = 1a + 1c threading mixed dislocations were propagated with large inclination angles more than four degrees from the c-axis to minimize elastic strain energy. The b = 1c threading edge dislocations had a large contrast difference of more than 0.4 in the photoluminescence image due to their strong nonradiative properties. Based on these characteristics obtained through multiphoton-excitation photoluminescence measurements, major types of dislocations (b = 1a, 1a + 1c, 1c) could statistically be identified.