Long carrier lifetimes in GaN epitaxial layers grown using TiN porous network templates

Improved structural quality and radiative efficiency were observed in GaN thin films grown by metalorganic chemical vapor deposition on TiN porous network templates formed by in situ thermal annealing of Ti in ammonia. The room-temperature decay times obtained from biexponential fits to time-resolved photoluminescence data are longer than ever reported for GaN. The carrier lifetime of 1.86 ns measured for a TiN network sample is slightly longer than that for a 200 μm thick high-quality freestanding GaN. The linewidth of the asymmetric x-ray diffraction (XRD) (101¯2) peak decreases considerably with the use of TiN layer and with increasing in situ annealing time, indicating the reduction in threading dislocation density. However, no direct correlation is yet found between the decay times and the XRD linewidths, suggesting that point defect and impurity related nonradiative centers are the main parameters affecting the lifetime.

[1]  Shuji Nakamura,et al.  Time-resolved photoluminescence spectroscopy in GaN-based semiconductors with micron spatial resolution , 2000 .

[2]  Yoshiki Naoi,et al.  A new method of reducing dislocation density in GaN layer grown on sapphire substrate by MOVPE , 2000 .

[3]  William H. Press,et al.  Numerical Recipes in FORTRAN - The Art of Scientific Computing, 2nd Edition , 1987 .

[4]  Luminescence transients in highly excited GaN grown by hydride vapor-phase epitaxy , 2004 .

[5]  S. Juršėnas,et al.  Decay of stimulated and spontaneous emission in highly excited homoepitaxial GaN , 2001 .

[6]  Akira Usui,et al.  Fabrication of Freestanding GaN Wafers by Hydride Vapor‐Phase Epitaxy with Void‐Assisted Separation , 2002 .

[7]  H. Morkoç,et al.  Luminescence properties of defects in GaN , 2005 .

[8]  Observation of long photoluminescence decay times for high-quality GaN grown by metalorganic chemical vapor deposition , 2000 .

[9]  P. Vennégués,et al.  Optimization of Si/N Treatment Time of Sapphire Surface and Its Effect on the MOVPE GaN Overlayers , 1999 .

[10]  John E. Bowers,et al.  Emission mechanisms of bulk GaN and InGaN quantum wells prepared by lateral epitaxial overgrowth , 1999 .

[11]  Hadis Morkoç,et al.  Characteristics of free-standing hydride-vapor- phase-epitaxy-grown GaN with very low defect concentration , 2000 .

[12]  Hadis Morkoç,et al.  Nitride Semiconductors and Devices , 1999 .

[13]  T. C. McGill,et al.  Minority carrier diffusion length and lifetime in GaN , 1998 .

[14]  Pierre Gibart,et al.  Epitaxial Lateral Overgrowth of GaN , 2001 .

[15]  G. Bunea,et al.  Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride vapor phase epitaxy , 1999 .

[16]  C. K. Inoki,et al.  Dislocation density reduction in GaN using porous SiN interlayers , 2005 .

[17]  William H. Press,et al.  Numerical recipes in C. The art of scientific computing , 1987 .

[18]  C. K. Inoki,et al.  Effectiveness of TiN porous templates on the reduction of threading dislocations in GaN overgrowth by organometallic vapor-phase epitaxy , 2005 .