Surface Morphology and Formation of Nanostructured Porous GaN by UV-assisted Electrochemical Etching

This article reports on the studies of porous GaN prepared by ultra-violet (UV) assisted electrochemical etching in a solution of 4:1:1 HF: CH3OH:H2O2 under illumination of an UV lamp with 500 W power for 10, 25 and 35 minutes. The optical properties of porous GaN sample were compared to the corresponding as grown GaN. Porosity induced photoluminescence (PL) intensity enhancement was found in these samples. The resulting porous GaN displays blue shifted PL spectra compared to the as-grown GaN. Appearance of the blue shifted emission is correlated with the development of highly anisotropic structures in the morphology. An estimate of the size of the GaN nanostructure can be obtained with the help of a quantized state effective mass theory.





References:
[1] H. Sohn, S. Letant, M. J. Sailor, W.C. Trogler, Detection of
Fluorophosphonate Chemical Warfare Agents by Catalytic Hydrolysis
with a Porous Silicon Interferometer, J. Am. Chem. Soc. 122 (2000) pp.
5399-5400.
[2] L.T. Canham, Silicon quantum wire array fabrication by electrochemical
and chemical dissolution of wafers, Appl. Phys. Lett. 57 (1990)
pp.1046-1048.
[3] A.G. Cullis, L.T. Canham, P. D.J. Calcott , The structural and
luminescence properties of porous silicon, J. Appl. Phys. 82 (1997)
pp.909-965.
[4] L. Brus, Luminescence of Silicon Materials: Chains, Sheets,
Nanocrystals, Nanowires, Microcrystals, and Porous Silicon, J. Phys.
Chem. 98 (1994) pp.3575-3581.
[5] V. S. Y Lin, K. Motesharei, K.P.S. Dancil, M.J. Sailor, M. R. Ghadiri, A
Porous Silicon-Based Optical Interferometric Biosensor , Science, 278
(1997) pp.840-843.
[6] P.M. Fauchet, L. Tsybeskov, C. Peng, S.P. Duttagupta, J. Von Behren, Y.
Kostoulas, J. M. V. Vandyshev, K. D. Hirschman, Light-emitting porous
silicon: materials science, properties, and device applications, IEEE J. Sel.
Top. Quantum Electron. 1, (1995) pp.1126-1139.
[7] F. Y. Soldatenkov, V. P. Ulin, A. A. Yakovenko, O. M. Fedorova, S. G.
Konnikov, V. I. Korol-kov, Unstrained epitaxial InxGa1−xAs films
obtained on porous GaAs, Tech. Phys. Lett. 25 (1999) pp.852-854.
[8] X. Li, Y-W Kim, P. W. Bohn, I. Adesida, In-plane bandgap control in
porous GaN through electroless wet chemical etching, Appl. Phys. Lett.
80 (2002) pp.980-982.
[9] C. K. Inoki, T.S. Kuan, C. D. Lee, A. Sagar, R. M. Feenstra, Growth of
GaN on Porous SiC Substrates by Plasma-Assisted Molecular Beam
Epitaxy,Mater. Res. Soc. Symp. Proc, 722 (2002) pp pp. K1.3.1-K.1.3.6.
[10] C. K. Inoki, T.S. Kuan, C. D. Lee, A. SAGAR, R. M. FEENSTRA, D. D.
KOLESKE, D. J. DIAZ, P. W. BOHN, I. ADESIDA, Growth of GaN on
Porous GaN and SiC Substrates,J. Electron. Mater. 32 (2003) pp.855-860.
[11] Physics of semiconductor nanostructures, edited by K.P. Jain (Narosa,
New Delhi, 1997).
[12] G. Fishman, I. Mihalcescu, R. Romestain, Effective-mass approximation
and statistical description of luminescence line shape in porous silicon,
Phys. Rev. B 48 (1993) pp.1464-1467.
[13] Y. H. Xie, M. S. Hybertsen, William L. Wilson, S. A. Ipri, G. E. Carver,
W. L. Brown, E. Dons, B. E. Weir, A. R. Kortan, G. P. Watson, and A. J.
Liddle, Absorption and luminescence studies of free-standing porous
silicon films, Phy. Rev. B 49 (1994) pp.5386-5397.
[14] G.C. John, V.A. Singh, Theory of the photoluminescence spectra of
porous silicon, Phys. Rev. B 50 (1994) pp.5329-5334.
[15] G.C. John, V.A. Singh, Porous silicon: theoretical studies, Phys. Rev. 263
(1995) pp.93-151.
[16] F.K. Yam, Z. Hassan, S.S. Ng, Porous GaN prepared by UV assisted
electrochemical etching, Thin Solid Films 515 (2007) pp.3469-3474.
[17] C. Adelmann, E. Martinez-Guerrero, F. Chabuel, J. Simon, B. Bataillou,
G. Mula, L. DANG, S. Pelekanos, T. B. Daudin, G. Feuillet, H. Mariette,
Growth and characterisation of self-assembled cubic GaN quantum dots,
Mater. Sci. Eng., B 82 (2001), pp.212-214.
[18] A. P. Vajpeyi, S. Tripathy, S. J. Chua, E. A. Fitzgerald, Investigation of
optical properties of nanoporous GaN films, Physica E, 28 (2005),
pp.141-149.
[19] H. Benisty, H. De Neve, C. Weisbuch, Impact of planar microcavity
effects on light extraction-Part I: basic concepts and analytical trends,
IEEE J. Sel. Top. Quantum Electron. 34 (1998), pp.1612-1631.
[20] E. F Schubert, Light-Emitting Diodes, Cambridge University Press, U.K,
2003.
[21] F.K. Yam, Z. Hassan, L.S. Chuah, Y.P. Ali, Investigation of structural and
optical properties of nanoporous GaN film, Applies Surface Science, vol
253 (2007) pp.7429-7434.
[22] D.J. Lockwood, P. Schmuki, H.J. Labbe, J.W. Fraser, Optical Properties
of Porous GaAs, Physica E 4 (1999) pp.102-110.
[23] H.C. Casey Jr., G.G. Fountain, R.G. Alley, B.P. Keller, S.P. Denbaars,
Low interface trap density for remote plasma deposited SiO2 on n-type
GaN, Applied Physics Letters 68 (1996) pp.1850-1852.