Optical polarization characteristics of ultraviolet (In)(Al)GaN multiple quantum well light emitting diodes
T. Kolbe1, A. Knauer2 , C. Chua3, Z. Yang3, S. Einfeldt2, P. Vogt1, N.M. Johnson3, M. Weyers2, and M. Kneissl1,2
Published in:
Appl. Phys. Lett., vol. 97, no. 171105 (2010).
Abstract:
The polarization of the in-plane electroluminescence of (0001) orientated (In)(Al)GaN multiple quantum well light emitting diodes in the ultraviolet-A and ultraviolet-B spectral range has been investigated. The intensity for transverse-electric polarized light relative to the transverse-magnetic polarized light decreases with decreasing emission wavelength. This effect is attributed to rearrangement of the valence bands at the Γ-point of the Brillouin zone with changing aluminum and indium mole fractions in the (In)(Al)GaN quantum wells. For shorter wavelength the crystal-field split-off hole band moves closer to the conduction band relative to the heavy and light hole bands and as a consequence the transverse-magnetic polarized emission becomes more dominant for deep ultraviolet light emitting diodes.
1 Institute of Solid State Physics, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
3 Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304, USA
© 2010 American Institute of Physics. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the American Institute of Physics..
Full version in pdf-format.