Comprehensive characterization of MOVPE-grown AlGaAs/AlAs distributed Bragg reflector structures by optical reflectance, X-ray diffraction and atomic force microscopy

A. Bhattacharya^a, M. Nasarek^b, U. Zeimer^b, A. Klein^b, M. Zorn^b, F. Bugge^b, S. Gramlich^b, M. Weyers^b

^a Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai, India
^b Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany

Published in:
Journal of Crystal Growth 274 (2005) 331-338.
© 1999-2005, Elsevier Science B.V.. 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 Elsevier Science B.V.

Abstract:
This paper reports on a comprehensive characterization of MOVPE-grown Al_xGa_1-xAs/AlAs distributed Bragg reflector (DBR) structures via optical reflectance, X-ray diffraction (XRD) and atomic force microscopy (AFM). These analytical techniques are used to investigate the influence of parameters like substrate misorientation, aluminum content and number of mirror pairs on the characteristics of high-reflectivity Al_xGa_1-xAs/AlAs-based Bragg mirrors. We find a strong correlation between the optical reflectivity of the DBR mirrors and the quality of X-ray rocking curves as well as the surface/interface roughness as measured by AFM. The data provided by these analytical techniques are used to optimize the DBR performance for its application invisible-wavelength vertical-cavity surface-emitting laser (VCSEL) diodes.

Keywords:
A1. High resolution X-ray diffraction; A1. Interfaces; A1. Optical reflectivity; A3. Metalorganic vapor phase epitaxy; A3. Superlattices; B2. Semiconducting aluminium compounds

Full version in pdf-format.