Effect of Surface Treatments on the Evolution of Microstructures in GaN Thin Films and GaN/AlGaN/GaN Heterostructures

  • Mansi AgrawalEmail author
  • B. R. Mehta
  • R. Muralidharan
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 215)


In this study the effect of hot phosphoric acid treatment on the evolution of microstructures in plasma assisted molecular beam epitaxy grown GaN thin films and GaN/AlGaN/GaN heterostructures is investigated. The surface morphology of the as grown samples and chemically treated samples is studied using field emission scanning electron microscopy which reveal the formation of different geometrical microstructures namely dodecagonal pyramids in one sample and hexagonal pits in the other after chemical treatment due to the different polar nature of GaN in both the samples.



Mansi Agrawal thanks Solid State Physics laboratory for the research funding. We also acknowledge the support of GaN MBE group and Characterization group at SSPL.


  1. 1.
    O. Ambacher, J. Smart, J.R. Shealy, N.G. Weimann, K. Chu, M. Murphy, W.J. Schaff, L.F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures. J. Appl. Phys. 85(6), 3222–3233 (1999)ADSCrossRefGoogle Scholar
  2. 2.
    F. Akyol, D.N. Nath, S. Krishnamoorthy, P.S. Park, S. Rajan, Suppression of electron overflow and efficiency droop in N-polar GaN green light emitting diodes. Appl. Phys. Lett. 100(11), 111118 (2012)ADSCrossRefGoogle Scholar
  3. 3.
    M. Stutzmann, O. Ambacher, M. Eickhoff, U. Karrer, A. Lima Pimenta, R. Neuberger, J. Schalwig, R. Dimitrov, P.J. Schuck, R.D. Grober, Playing with polarity. Physica Status Solidi (b) 228, 505–512 (2001)ADSCrossRefGoogle Scholar
  4. 4.
    S.L. Qi, Z.Z. Chen, H. Fang, Y.J. Sun, L.W. Sang, X.L. Yang, L.B. Zhao, P.F. Tian, J.J. Deng, Y.B. Tao, T.J. Yu, Z.X. Qin, G.Y. Zhang, Study on the formation of dodecagonal pyramid on nitrogen polar GaN surface etched by Hot H3PO4. J. Appl. Phys. Lett. 95, 071–114 (2009)CrossRefGoogle Scholar
  5. 5.
    S. Keller, Y. Dora, F. Wu, X. Chen, S. Chowdury, S.P. DenBaars, J.S. Speck, U.K. Mishra, Properties of N-polar GaN films and AlGaN/GaN heterostructures grown on (111) silicon by metal organic chemical vapor deposition. Appl. Phys. Lett. 97(14), 142109 (2010)ADSCrossRefGoogle Scholar
  6. 6.
    R. Dimitrov, M. Murphy, J. Smart, W. Schaff, J.R. Shealy, L.F. Eastman, O. Ambacher, M. Stutzmann, Two-dimensional electron gases in Ga-face and N-face AlGaN/GaN heterostructures grown by plasma-induced molecular beam epitaxy and metalorganic chemical vapor deposition on sapphire. J. Appl. Phys. 87(7), 3375–3380 (2000)ADSCrossRefGoogle Scholar
  7. 7.
    U. Karrer, O. Ambacher, M. Stutzmann, Influence of crystal polarity on the properties of Pt/GaN Schottky diodes. Appl. Phys. Lett. 77(13), 2012–2014 (2000)ADSCrossRefGoogle Scholar
  8. 8.
    Y.L. Wang, B.H. Chu, C.Y. Chang, K.H. Chen, Y. Zhang, Q. Sun, J. Han, S.J. Pearton, F. Ren, Hydrogen sensing of N-polar and Ga-polar GaN Schottky diodes. Sens. Actuators B Chem. 142(1), 175–178 (2009)CrossRefGoogle Scholar
  9. 9.
    M.H. Wong, S. Keller, S.D. Nidhi, D.J. Denninghoff, S. Kolluri, D.F. Brown, J. Lu, N.A. Fichtenbaum, E. Ahmadi, U. Singisetti, N-polar GaN epitaxy and high electron mobility transistors. Semicond. Sci. Technol. 28(7), 074009 (2013)ADSCrossRefGoogle Scholar
  10. 10.
    S. Rajan, A. Chini, M.H. Wong, J.S. Speck, U.K. Mishra, N-polar GaN∕ Al GaN∕ GaN high electron mobility transistors. J. Appl. Phys. 102(4), 044501 (2007)ADSCrossRefGoogle Scholar
  11. 11.
    S. Dasgupta, D.F. Nidhi Brown, F. Wu, S. Keller, J.S. Speck, U.K. Mishra, Ultralow nonalloyed ohmic contact resistance to self-aligned N-polar GaN high electron mobility transistors by In (Ga) N regrowth. Appl. Phys. Lett. 96(14), 143504 (2010)ADSCrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of PhysicsIndian Institute of Technology DelhiHauz Khas, New DelhiIndia
  2. 2.Centre for Nano Science and Engineering, Indian Institute of ScienceBangaloreIndia

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