Abstract
Photo-electrochemical, bandgap selective, lateral etching is used to create 200 nm-thick, ultra-smooth GaN membranes, containing 10 pairs of GaN/AlGaN quantum wells. The use of electrolyte concentrations as low as 0.0004 M, along with appropriate excitation power and bias conditions, are shown to enhance the quality of freestanding membranes immensely, with an AFM roughness of 0.65 nm; the best ever reported value for GaN membranes fabricated using a similar technique. Transmission and photoluminescence experiments on these membranes were made possible at cryogenic temperatures by membrane transferring onto a double-side polished sapphire substrate, revealing pronounced excitonic features; the analysis of which strongly suggest that the absorption coefficients of GaN are at least 30 % higher than the values previously reported in the literature.
Similar content being viewed by others
References
Nakamura S (1999) InGaN-based violet laser diodes. Semicond Sci Technol 14:R27–R40. doi:10.1088/0268-1242/14/6/201
Bandić ZZ, Bridger PM, Piquette EC et al (1999) High voltage (450 V) GaN Schottky rectifiers. Appl Phys Lett 74:1266. doi:10.1063/1.123520
Muth JF, Lee JH, Shmagin IK et al (1997) Absorption coefficient, energy gap, exciton binding energy, and recombination lifetime of GaN obtained from transmission measurements. Appl Phys Lett 71:2572. doi:10.1063/1.120191
Sturge M (1962) Optical absorption of gallium arsenide between 0.6 and 2.75 eV. Phys Rev 127:768–773. doi:10.1103/PhysRev.127.768
Johnson WC, Parson JB, Crew MCC (1931) Nitrogen compounds of gallium III. J Phys Chem 36:2651–2654. doi:10.1021/j150340a015
Adesida I, Mahajan A, Andideh E et al (1993) Reactive ion etching of gallium nitride in silicon tetrachloride plasmasa. Appl Phys Lett 63:2777. doi:10.1063/1.110331
Pearton SJ (1993) Dry and wet etching characteristics of InN, AlN, and GaN deposited by electron cyclotron resonance metalorganic molecular beam epitaxy. J Vac Sci Technol A 11:1772. doi:10.1116/1.578423
Shul RJ, McClellan GB, Casalnuovo Sa et al (1996) Inductively coupled plasma etching of GaN. Appl Phys Lett 69:1119. doi:10.1063/1.117077
Ping AT, Adesida I, Asif Khan M (1995) Study of chemically assisted ion beam etching of GaN using HCl gas. Appl Phys Lett 67:1250. doi:10.1063/1.114387
Youtsey C, Adesida I, Bulman G (1997) Highly anisotropic photo enhanced wet etching of n-type GaN. Appl Phys Lett 71:2151. doi:10.1063/1.119365
Minsky MS, White M, Hu EL (1996) Room-temperature photo enhanced wet etching of GaN. Appl Phys Lett 68:1531. doi:10.1063/1.115689
Haberer ED, Sharma R, Meier C et al (2004) Free-standing, optically pumped, GaN/InGaN microdisk lasers fabricated by photoelectrochemical etching. Appl Phys Lett 85:5179. doi:10.1063/1.1829167
Youtsey C, Adesida I, Romano LT, Bulman G (1998) Smooth n-type GaN surfaces by photo enhanced wet etching. Appl Phys Lett 72:560. doi:10.1063/1.120758
Peng L-H, Chuang C-W, Ho J-K et al (1998) Deep ultraviolet enhanced wet chemical etching of gallium nitride. Appl Phys Lett 72:939. doi:10.1063/1.120879
Trichas E, Kayambaki M, Iliopoulos E et al (2009) Resonantly enhanced selective photochemical etching of GaN. Appl Phys Lett 94:173505. doi:10.1063/1.3122932
Trichas E, Pelekanos NT, Iliopoulos E et al (2011) Bragg polariton luminescence from a GaN membrane embedded in all dielectric microcavity. Appl Phys Lett 98:221101. doi:10.1063/1.3595481
Trichas E, Xenogianni C, Kayambaki M et al (2008) Selective photochemical etching of GaN films and laser lift-off for microcavity fabrication. Phys Status Solidi 205:2509–2512. doi:10.1002/pssa.200780215
Shan W, Schmidt TJ, Yang XH et al (1995) Temperature dependence of interband transitions in GaN grown by metalorganic chemical vapor deposition. Appl Phys Lett 66:985. doi:10.1063/1.113820
Shan W, Fischer aJ, Hwang SJ et al (1998) Intrinsic exciton transitions in GaN. J Appl Phys 83:455–461. doi:10.1063/1.366660
Kornitzer K, Ebner T, Grehl M et al (1999) High-resolution photoluminescence and reflectance spectra of homoepitaxial GaN layers. Phys Status Solid 216:5–9
Li CF, Huang YS, Malikova L, Pollak FH (1997) Temperature dependence of the energies and broadening parameters of the interband excitonic transitions in wurtzite GaN. Phys Rev B 55:9251–9254. doi:10.1103/PhysRevB.55.9251
Acknowledgements
This work was supported by the European Initial Training Network ‘ICARUS’ and by the European Social Fund and National resources through the THALES programme ‘NANOPHOS’.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Jayaprakash, R., Kalaitzakis, F.G., Kayambaki, M. et al. Ultra-smooth GaN membranes by photo-electrochemical etching for photonic applications. J Mater Sci 49, 4018–4024 (2014). https://doi.org/10.1007/s10853-014-8071-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10853-014-8071-0