High spectral uniformity of AlGaN with a high Al content evidenced by scanning near-field photoluminescence spectroscopy

Scanning near-field photoluminescence (PL) spectroscopy was applied to study spatial variations of emission spectra of AlxGa1−xN epilayers with 0.6≤x≤0.7. PL spectra were found to be spatially uniform with peak wavelength standard deviations of only ∼2 meV and ratios between peak intensity standard deviations and average peak intensity values of 0.06. The observed absence of correlation between the PL peak wavelength and intensity shows that spatial distribution of nonradiative recombination centers is not related to band potential fluctuations. Our results demonstrate that the homogeneous broadening and the random cation distribution primarily determine PL linewidths for layers grown under optimized conditions.

[1]  Jacek A. Majewski,et al.  Pyroelectric properties of Al(In)GaN/GaN hetero- and quantum well structures , 2002 .

[2]  M. Shur,et al.  Carrier lifetimes in AlGaN quantum wells: electric field and excitonic effects , 2008 .

[3]  Cheul‐Ro Lee,et al.  EXCITON-PHONON INTERACTIONS, EXCITON BINDING ENERGY, AND THEIR IMPORTANCE IN THE REALIZATION OF ROOM-TEMPERATURE SEMICONDUCTOR LASERS BASED ON GAN , 1998 .

[4]  Tsunemasa Taguchi,et al.  Localization-induced inhomogeneous screening of internal electric fields in AlGaN-based quantum wells , 2007 .

[5]  R. Gaska,et al.  Reliability of Deep-UV Light-Emitting Diodes , 2008, IEEE Transactions on Device and Materials Reliability.

[6]  Yoichi Kawakami,et al.  Nanoscopic recombination processes in InGaN/GaN quantum wells emitting violet, blue, and green spectra , 2008 .

[7]  S. Denbaars,et al.  Carrier redistribution between different potential sites in semipolar (202¯1) InGaN quantum wells studied by near-field photoluminescence , 2014 .

[8]  A. Uedono,et al.  Radiative and nonradiative processes in strain-free AlxGa1−xN films studied by time-resolved photoluminescence and positron annihilation techniques , 2004 .

[9]  H. Amano,et al.  PHOTOLUMINESCENCE INVESTIGATIONS OF ALGAN ON GAN EPITAXIAL FILMS , 1999 .

[10]  Arto V. Nurmikko,et al.  Role of localized and extended electronic states in InGaN/GaN quantum wells under high injection, inferred from near-field optical microscopy , 1998 .

[11]  Uwe Rossow,et al.  Localized high-energy emissions from the vicinity of defects in high-efficiency Ga x In 1-x N/GaN quantum wells , 2005 .

[12]  Michael S. Shur,et al.  Aging of AlGaN quantum well light emitting diode studied by scanning near-field optical spectroscopy , 2009 .

[13]  K. Ploog,et al.  Lateral phase separation in AlGaN grown on GaN with a high-temperature AlN interlayer , 2005 .

[14]  M. Shur,et al.  Deep-Ultraviolet Light-Emitting Diodes , 2010, IEEE Transactions on Electron Devices.

[15]  M. Shur,et al.  Dynamics of carrier recombination and localization in AlGaN quantum wells studied by time-resolved transmission spectroscopy , 2009 .

[16]  Michael Wraback,et al.  High power AlGaN ultraviolet light emitters , 2014 .

[17]  James S. Speck,et al.  Optical properties of extended and localized states in m-plane InGaN quantum wells , 2013 .

[18]  M. Khan,et al.  Role of alloy fluctuations in photoluminescence dynamics of AlGaN epilayers , 2006 .

[19]  K. B. Nam,et al.  Optical properties of AlN and GaN in elevated temperatures , 2004 .

[20]  Yu Cao,et al.  Compositional modulation and optical emission in AlGaN epitaxial films , 2006 .

[21]  Michael S. Shur,et al.  Localization potentials in AlGaN epitaxial films studied by scanning near-field optical spectroscopy , 2011 .

[22]  Hongxing Jiang,et al.  Exciton localization in AlGaN alloys , 2006 .

[23]  A. Uedono,et al.  Collateral evidence for an excellent radiative performance of AlxGa1−xN alloy films of high AlN mole fractions , 2011 .

[24]  S. Denbaars,et al.  Near-field investigation of spatial variations of (202̄1̄) InGaN quantum well emission spectra , 2013 .

[25]  Jianping Li,et al.  Characteristics of high Al content AlxGa1-xN grown by metalorganic chemical vapor deposition , 2007, Microelectron. J..

[26]  Yoichi Kawakami,et al.  Nanoscopic Photoluminescence Properties of a Green-Emitting InGaN Single Quantum Well on a {2021} GaN Substrate Probed by Scanning Near-Field Optical Microscopy , 2012 .

[27]  Michael S. Shur,et al.  Optical studies of degradation of AlGaN quantum well based deep ultraviolet light emitting diodes , 2010 .

[28]  S. M. Lee,et al.  A quantum statistical theory of linewidths of radiative transitions due to compositional disordering in semiconductor alloys , 1993 .