Remarkable enhancement of 254‐280 nm deep ultraviolet emission from AlGaN quantum wells by using high‐quality AlN buffer on sapphire

Abstract

Abstract We observed remarkable enhancement of 254‐280 nm deep ultraviolet (UV) emission from AlGaN multi quantum wells (MQWs) by using low threading dislocation density (TDD) AlN templates on sapphire substrates. High‐quality AlN templates were fabricated using ammonia pulse‐flow multi‐layer (ML) AlN growth technique by metal‐organic chemical vapor deposition (MOCVD). The photoluminescence (PL) intensity of AlGaN‐QW with emission wavelength of 280 nm was increased by approximately 30 times by reducing the full width at half‐maximum (FWHM) of X‐ray diffraction (102) ω‐scan rocking curve (XRC) of AlGaN buffer on ML‐AlN from 1214 to 488 arcsec. We obtained similar emission enhancement for AlGaN QWs with emission wavelengths of 254, 260 and 270 nm. We found that PL intensity of the QWs were rapidly increased when FWHM of XRC (102) is reduced as narrow as 800‐1000 arcsec. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)