Optical properties of GaN
- 123 Downloads
GaN is one of the most promising semiconductors for optoelectronics in the blue spectral region. The commercialization of bright blue and green light emitting diodes based on group-III nitrides is a milestone in the competition for blue light sources which are important for fabricating full-color displays. The recent first realization of an InGaN multi-quantum-well laser diode yields a great stride of progress in the development of ultraviolet optoelectronic devices. In spite of this recent success in device techniques, some of the basic electrical and optical properties of group-III nitrides are still unknown. Little information exists on compensation and conduction mechanisms in GaN. This is often a problem of the material quality and a lack of better understanding of the epitaxial growth techniques.
We will present time-integrated and time-resolved photoluminescence investigations from the band edge down to the near infrared spectral region to provide information about excitonic properties as well as the influence of point and extended defects in cubic and hexagonal GaN. Using calorimetric-absorption,-transmission and-reflection spectroscopy the excitonic transitions originating from the A-, B-, and C-valence bands are precisely determined and the crystal-field and spin-orbit-splitting energies are calculated. These splittings are strongly influenced by the lattice mismatch and the thermal expansion coefficients between the GaN epilayer and the substrate. The dynamical behavior of the free and bound excitons in GaN clearly gives evidence of nonradiative decay channels. Calorimetric spectroscopy yields typical quantum efficiencies of 25% for the free exciton and of 50% for the donor-bound exciton in undoped samples.
Spatially resolved Raman-scattering and photoluminescence experiments allow to analyze the crystal structure, layer orientation and strain contribution to the lattice properties. Epitaxial growth of GaN on GaAs shows a cubic phase purity up to 98%. Spatially resolved investigations demonstrate that the yellow luminescence in GaN with its maximum at 2.4 eV is strongly localized near the interface.
Photoluminescence and optical gain measurements of highly excited GaN are reported. The decay of biexcitons is observed for the first time in a III–V semiconductor. At higher temperatures inelastic scattering processes of excitons, phononassisted annihilation of excitons and free carriers dominate. Similar characteristics are observed in temperature-dependent gain measurements.
Unable to display preview. Download preview PDF.
- S. Nakamura, Ist. Phys. conf. Ser. No 142: Chapter 6, paper presented at Silicon Carbide and Related Materials 1995 Conf., Kyoto, Japan, 1996 ed. by S. Nakashima, H. Matsunami, S. Yoshida and H. Harima, IOP Publishing Ltd, p. 979Google Scholar
- A. Ishibashi, Proc. International Symposium on Blue Laser and Light Emitting Diodes, Chiba University, Japan, March 1996, ed. A. Yoshikawa, K. Kihino, M. Kobayashi, T. Yasuda, p. 113Google Scholar
- S. Nakamura, Proc. International Symposium on Blue Laser and Light Emitting Diodes, Chiba University, Japan, March 1996, ed. A. Yoshikawa, K. Kihino, M. Kobayashi, T. Yasuda, p. 119Google Scholar
- B. Monemar, J. P. Bergman, H. Amano, T. Detchprohm, K. Hiramatsu, and N. Sawaki, Proc. Intern, Symposium on Blue Laser and Light Emmitting Diodes, Chiba University, Japan, March 1996, ed. A. Yoshikawa, K. Kihino, M. Kobayashi, T. Yasuda, p. 135Google Scholar
- D. Schikora, D. J. As, M. Hankeln, K. Lischka, T. Burow, F. Henneberger, T. Litz, A. Waag, Proc. of the First European Workshop on GaN EGW-1, Rigi, Switzerland, to be published in MRS Proc. vol. xxx (1996)Google Scholar
- L. Eckey, L. Podlowski, A. Göldner, A. Hoffmann, I. Broser, B. K. Meyer, D. Volm, T. Streibl, T. Detchprohm, K. Hiramatsu, H. Amano, I. Akasaki, Ist. Phys. conf. Ser. No 142: Chapter 6, paper presented at Silicon Carbide and Related Materials 1995 Conf., Kyoto, Japan, ed. by S. Nakashima, H. Matsunami, S. Yoshida and H. Harima, IOP Publishing Ltd, p. 927Google Scholar
- D. Volm, K. Oettinger, T. Streibl, D. Kovalev, M. Ben-Chorin, J. Diener, B.K. Meyer, J. Majewski, L. Eckey, A. Hoffmann, H. Amano, I. Akasaki, K. Hiramatsu, T. Detchprohm, (published in Phys. Rev.)Google Scholar
- L. Eckey, A. Hoffmann, R. Heitz, I. Broser, B.K. Meyer, T. Detchprohm, K. Hiramatsu, H. Amano, and I. Akasaki, 1st Int. Symposium on GaN and Related Materials, ed. R.D. Dupuis, S. Nakamura, F.A. Ponce, J.A. Edmund, Material Research Soc. Symp. Boston (1995), Vol. 395Google Scholar
- A. Hangleiter, T. Forner, Jin-Seo Im, V. Härle, F. Scholz, 1st Int. Symposium on GaN and Related Materials, ed. R.D. Dupuis, S. Nakamura, F. A. Ponce, J. A. Edmund, Material Research Soc. Symp. Boston (1995), Vol. 395 Google Scholar
- L. Eckey, J. Holst, A. Hoffmann, I. Broser, T. Detchprohm, K. Hiramatsu, Proc. 1st Int. European Workshop on GaN, Rigi (CH), 1996Google Scholar
- M. Smith, G.D. Chen, J. Y. Lin, H.k. Jiang, A. Salvador, W. Kim, ž. Aktas, A. Botchkarev, H. Morkoç, and B. Goldenberg, 67 (1995), 3387Google Scholar
- C. Johnson, J.Y. Lin, H. X. Jiang, M. Asif Khan, and C.J. Sun, Appl. Phys. Lett. xx (1996), xxGoogle Scholar
- P. Thurian, L. Eckey, H. Siegle, J. Holst, P. Maxim, R. Heitz, A. Hoffmann, Ch. Thomsen, I. Broser, K. Pressel, I. Akasaki, H. Amano, K. Hiramatsu, T. Detchprohm, D. Schikora, M. Hankeln, K. Lischka Proc. Intern, Symposium on Blue Laser and Light Emmitting Diodes, Chiba University, Japan, March 1996, ed. A. Yoshikawa, K. Kihino, M. Kobayashi, T. Yasuda, p. 180Google Scholar
- L. Eckey, A. Hoffmann, D. Schikora, M. Hankeln, to be publishedGoogle Scholar
- Jörg Neugebauer and Chris G. Van de Walle, Appl. Phys. Lett. issue 22.7.1996Google Scholar
- A. Hoffmann, L. Eckey, P. Maxim, J.-Chr. Holst, R. Heitz, D.M. Hofmann, D. Kovalev, G. Steude, D. Volm, B.K. Meyer, T. Detchprohm, H. Amano, I. Akasaki Proc. 1st Topical Workshop on III–V Nitrides, TWN’95, Nagoya, (1995), published in Solid State Electronics (1996).Google Scholar
- R. Heitz, P. Maxim, L. Eckey, P. Thurian, I. Broser, K. Pressel, B.K. Meyer, Phys. Rev. B, accepted for publicationGoogle Scholar
- J.C. Phillips, Phys. Rev. 42 (1970), 317Google Scholar
- Numerical data and functions in science and technology/Landolt-Börnstein, Vol. III/17 a, Springer-Verlag, Berlin, Heidelberg, New York, 1982Google Scholar