Nanoporous InGaN of high In composition prepared by KOH electrochemical etching

Abstract The fabrication of porous InGaN of high In composition ~47% using UV-assisted electrochemical etching in a diluted solution of KOH is demonstrated for the first time. In this paper, the effect of etching time on the morphology of porous InGaN was investigated using field emission scanning electron microscopy (FE-SEM). Pore size and density were found to increase with increasing etching time. In addition, the etching activity at grain boundaries became significant for longer etching periods in which more defective region at grain boundaries had been etched. The reduction in dislocation density due to the etching process was confirmed by a decreased value of the full width at half maximum (FWHM) from high resolution x-ray diffraction (HR-XRD) rocking curve measurements for all porous samples. Porous samples exhibited red-shift characteristics in photoluminescence (PL) spectra with respect to the as-grown sample due to relaxation of compressive stress. Furthermore, the PL intensity of porous samples showed stronger signals relative to the as-grown sample, which is attributed to both the reduction of dislocation density and multiple light scattering from the crystallite sidewalls. Such properties indicate the potential of porous InGaN for applications in optical and sensor devices.

[1]  S. Pearton,et al.  UV-photoassisted etching of GaN in KOH , 1999 .

[2]  M. Kurouchi,et al.  Effect of low-temperature InGaN interlayers on structural and optical properties of In-rich InGaN , 2007 .

[3]  Soo Jin Chua,et al.  Reduction of threading dislocation density in GaN grown on strain relaxed nanoporous GaN template , 2007 .

[4]  Z. Hassan,et al.  Porous GaN prepared by UV assisted electrochemical etching , 2007 .

[5]  Sang-Wan Ryu,et al.  Optical characterization of nanoporous GaN by spectroscopic ellipsometry , 2012 .

[6]  Soo Jin Chua,et al.  High Optical Quality Nanoporous GaN Prepared by Photoelectrochemical Etching , 2005 .

[7]  Growth and characterization of GaN films on Si(111) substrate using high-temperature AlN buffer layer , 2005 .

[8]  S. Moisa,et al.  Ultraviolet photoenhanced wet etching of GaN in K2S2O8 solution , 2001 .

[9]  Z. Hassan,et al.  Investigation of structural and optical properties of nanoporous GaN film , 2007 .

[10]  N. Park,et al.  Metalorganic Molecular Beam Epitaxy of GaN Thin Films on a Sapphire Substrate , 2000 .

[11]  T. L. Williamson,et al.  Morphology evolution and luminescence properties of porous GaN generated via Pt-assisted electroless etching of hydride vapor phase epitaxy GaN on sapphire , 2003 .

[12]  Soo Jin Chua,et al.  Influence of Rapid Thermal Annealing on the Luminescence Properties of Nanoporous GaN Films , 2006 .

[13]  Soo Jin Chua,et al.  Investigation of optical properties of nanoporous GaN films , 2005 .

[14]  Xiaoqing Xu,et al.  Investigation of cracks in GaN films grown by combined hydride and metal organic vapor-phase epitaxial method , 2011, Nanoscale research letters.

[15]  H. Hwang,et al.  Photoelectrochemical etching of InxGa1−xN , 2000 .

[16]  Ian T. Ferguson,et al.  Characterization of InN layers grown by high-pressure chemical vapor deposition , 2006 .

[17]  Joan J. Carvajal,et al.  Morphology Control in As-Grown GaN Nanoporous Particles , 2009 .

[18]  E. Fitzgerald,et al.  Fabrication and characterization of nano‐porous GaN template for strain relaxed GaN growth , 2007 .

[19]  Michelle A. Moram,et al.  X-ray diffraction of III-nitrides , 2009 .

[20]  Hao Wu,et al.  Improvement of structural and electrical properties of Cu2O films with InN epilayers , 2011 .

[21]  C. Duan,et al.  Temperature dependent photoluminescence of porous InP , 2001 .

[22]  H. Xiao,et al.  Effect of AlN buffer thickness on GaN epilayer grown on Si(1 1 1) , 2011 .

[23]  Shi-Hai Sun,et al.  The surface topography of GaN grown on Si (1 1 1) substrate before and after wet chemical etching , 2006 .

[24]  Hongxing Jiang,et al.  Single phase InxGa1−xN(0.25≤x≤0.63) alloys synthesized by metal organic chemical vapor deposition , 2008 .

[25]  M. Hashim,et al.  Enhancing hydrogen sensitivity of porous GaN by using simple and low cost photoelectrochemical etching techniques , 2012 .

[26]  P. Bohn,et al.  Nanoporous Ag–GaN thin films prepared by metal‐assisted electroless etching and deposition as three‐dimensional substrates for surface‐enhanced Raman scattering , 2012 .

[27]  K. D. Mynbaev,et al.  Structural characterization and strain relaxation in porous GaN layers , 2000 .

[28]  N. K. Ali,et al.  Effect of different electrolytes on porous GaN using photo-electrochemical etching , 2011 .

[29]  E. Fitzgerald,et al.  Effect of carrier density on the surface morphology and optical properties of nanoporous GaN prepared by UV assisted electrochemical etching , 2007 .

[30]  Xiaohui Wang,et al.  Growth of crack-free GaN films on Si(111) substrate by using Al-rich AlN buffer layer , 2004 .

[31]  I. Adesida,et al.  Morphology and luminescence of porous GaN generated via Pt-assisted electroless etching , 2002 .