Excitonic recombination in epitaxial lateral overgrown AlN on sapphire

Excitonic emission in heteroepitaxially grown aluminum nitride (AlN) with reduced defect density due to the epitaxial lateral overgrowth (ELO) of patterned AlN/sapphire templates has been investigated by photoluminescence spectroscopy and compared to AlN/sapphire and homoepitaxially grown AlN. The ELO sample exhibits small linewidths of the free exciton and two different bound exciton emission bands. The free exciton emission energy is shifted by 58.5 meV with respect to unstrained homoepitaxially grown AlN attributed to compressive strain. A donor bound exciton D0X with an exciton localization energy of 13.0–13.5 meV is dominating in the photoluminescence spectra of ELO AlN/sapphire. This D0X does not show strong phonon replica and is dominant at elevated temperatures in ELO AlN/sapphire. The optical quality of heteroepitaxial AlN is significantly improved using the ELO technique and therefore suitable for high efficiency ultraviolet light emitters.

[1]  T. Wunderer,et al.  Direct determination of the silicon donor ionization energy in homoepitaxial AlN from photoluminescence two-electron transitions , 2013 .

[2]  U. Zeimer,et al.  High quality AlGaN grown on ELO AlN/sapphire templates , 2013 .

[3]  M. Funato,et al.  Complete set of deformation potentials for AlN determined by reflectance spectroscopy under uniaxial stress , 2013 .

[4]  T. Kimoto,et al.  Optical Properties of Highly Strained AlN Coherently Grown on 6H-SiC(0001) , 2013 .

[5]  U. Zeimer,et al.  Controlled coalescence of MOVPE grown AlN during lateral overgrowth , 2013 .

[6]  U. Zeimer,et al.  AlGaN layer structures for deep UV emitters on laterally overgrown AlN/sapphire templates , 2013 .

[7]  Z. Sitar,et al.  Strain relaxation by pitting in AlN thin films deposited by metalorganic chemical vapor deposition , 2013 .

[8]  C. Cobet,et al.  Negative spin-exchange splitting in the exciton fine structure of AlN , 2013 .

[9]  M. Weyers,et al.  Modulated Epitaxial Lateral Overgrowth of AlN for Efficient UV LEDs , 2012, IEEE Photonics Technology Letters.

[10]  Ryan G. Banal,et al.  Homoepitaxy and Photoluminescence Properties of (0001) AlN , 2012 .

[11]  K. Thonke,et al.  Optical identification of silicon as a shallow donor in MOVPE grown homoepitaxial AlN , 2012 .

[12]  A. Winnacker,et al.  Growth of AlN bulk crystals on SiC seeds: Chemical analysis and crystal properties , 2012 .

[13]  U. Zeimer,et al.  (Al,Ga)N overgrowth over AlN ridges oriented in [1120] and [1100] direction , 2011 .

[14]  K. Thonke,et al.  Sharp bound and free exciton lines from homoepitaxial AlN , 2011 .

[15]  C. Cobet,et al.  Influence of exciton-phonon coupling and strain on the anisotropic optical response of wurtzite AlN around the band edge , 2011 .

[16]  E. Janzén,et al.  Shallow donor and DX states of Si in AlN , 2011 .

[17]  Motoaki Iwaya,et al.  Improved Efficiency of 255–280 nm AlGaN-Based Light-Emitting Diodes , 2010 .

[18]  Norihiko Kamata,et al.  222–282 nm AlGaN and InAlGaN‐based deep‐UV LEDs fabricated on high‐quality AlN on sapphire , 2009 .

[19]  Michael Heuken,et al.  Effect of the AIN nucleation layer growth on AlN material quality , 2008 .

[20]  K. Thonke,et al.  Cathodoluminescence, photoluminescence, and reflectance of an aluminum nitride layer grown on silicon carbide substrate , 2007 .

[21]  W. Paszkowicz,et al.  Rietveld-refinement study of aluminium and gallium nitrides , 2004 .

[22]  Mim Lal Nakarmi,et al.  AlGaN-based ultraviolet light-emitting diodes grown on AlN epilayers , 2004 .

[23]  K. B. Nam,et al.  Unique optical properties of AlGaN alloys and related ultraviolet emitters , 2004 .

[24]  Hongxing Jiang,et al.  Band-edge photoluminescence of AlN epilayers , 2002 .

[25]  M. Shur,et al.  Near-band-edge photoluminescence of wurtzite-type AlN , 2002 .

[26]  R. Dimitrov,et al.  DX-behavior of Si in AlN , 2000 .

[27]  V. Walle,et al.  DX-center formation in wurtzite and zinc-blende Al x Ga 1-x N , 1998 .

[28]  Manijeh Razeghi,et al.  High quality AIN and GaN epilayers grown on (00⋅1) sapphire, (100), and (111) silicon substrates , 1995 .

[29]  M. Weyers,et al.  Advances in group III-nitride-based deep UV light-emitting diode technology , 2010 .