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Photoluminescence characteristics of polar and nonpolar AlGaN/GaN superlattices

2010; American Institute of Physics; Volume: 97; Issue: 12 Linguagem: Inglês

10.1063/1.3493185

1520-8842

Z. Vashaei, C. Bayram, Pierre Lavenus, Manijeh Razeghi,

ZnO doping and properties

High quality Al0.2Ga0.8N/GaN superlattices (SLs) with various (GaN) well widths (1.6 to 6.4 nm) have been grown on polar c-plane and nonpolar m-plane freestanding GaN substrates by metal-organic chemical vapor deposition. Atomic force microscopy, high resolution x-ray diffraction, and photoluminescence (PL) studies of SLs have been carried out to determine and correlate effects of well width and polarization field on the room-temperature PL characteristics. A theoretical model was applied to explain PL energy-dependency on well width and crystalline orientation taking into account internal electric field for polar substrate. Absence of induced-internal electric field in nonpolar SLs was confirmed by stable PL peak energy and stronger PL intensity as a function of excitation power density than polar ones.