Optical Characterization of Defect-Related Carrier Recombination and Transport Features in GaN Substrates and CVD Diamonds

Abstract

Defect related carrier recombination and transport properties have been investigated in differently doped HVPE GaN substrates and CVD diamond layers. Carrier generation by interband transitions or by deep-defect photoexcitation were realized for studies of GaN samples by using picosecond pulses at 351 nm or 527 nm. This allowed to create favorable conditions for radiative and nonradiative recombination in the crystals and reveal peculiarities of photoelectrical properties of high and low density plasma in undoped, doped, and compensated GaN. In CVD diamonds, carrier diffusion length was found equal to ~ 0.5 μm and non-dependent on nitrogen density, while the carrier lifetime varied from 0.2 to 0.6 ns.