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Optical properties of low-dimensional nitride semiconductors

Raphaël Butté 

Institute of Quantum Electronics and Photonics Ecole Polytechnique Federale de Lausanne, Lausanne CH-1015, Switzerland


The main optical properties of III-nitride (III-N) heterostructures will be reviewed. We shall first define spontaneous and piezoelectric polarizations which are inherent to III-N semiconductors crystallizing with the wurtzite phase [1]. It will be shown that polarization discontinuities are responsible for the built-in electric field present in III-N heterostructures grown along the c-axis [2]. The physics will be illustrated by considering low Al content GaN/AlGaN quantum wells (QWs) [3], which exhibit a quality allowing probing their intrinsic properties. In particular, we shall describe the experimental signature of the quantum confined Stark effect (QCSE) [4] and the subsequent decrease of the radiative efficiency of QWs with increasing well thickness. The observation of well-resolved A and B excitonic resonances in the reflectivity spectra of high quality GaN QWs [5] and the biexcitonic properties of the latter [6] will be treated. The possible origins explaining the high quantum efficiency of In-based III-N QWs, which are presently at the heart of the huge success of UV-blue III-N optoelectronic devices, will also be discussed [7]. Finally, the concept of non- and semi-polar QWs, where the QCSE is either suppressed or decreased, for the realization of more efficient light-emitters will be introduced [8].

[1] F. Bernardini, V. Fiorentini, and D. Vanderbilt, Phys. Rev. B 56, R10024 (1997)

[2] See, e.g., R. Butté and N. Grandjean, in Polarization Effects in Semiconductors, ed. by C. Wood and D. Jena (Springer, New York, 2008)

[3] E. Feltin et al., Appl. Phys. Lett. 90, 021905 (2007)

[4] M. Leroux et al., Phys. Rev. B 58, R13371 (1998)

[5] F. Stokker-Cheregi et al., Phys. Rev. B 79, 245316 (2009)

[6] F. Stokker-Cheregi et al., Phys. Rev. B 77, 125342 (2008); ibid., Appl. Phys. Lett. 93, 152105 (2008)

[7] See, e.g., S. Nakamura, Science 281, 956 (1998); S. Pimputkar et al., , Nature. Photon. 3, 180 (2009)

[8] P. Waltereit et al., Nature (London) 406, 865 (2000)


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Presentation: Keynote lecture at E-MRS Fall Meeting 2009, Symposium A, by Raphaël Butté
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-07-23 16:10
Revised:   2009-07-23 16:10