J. Phys. Colloques
Volume 48, Numéro C5, Novembre 19873rd International Conference on Modulated Semiconductor Structures
|Page(s)||C5-435 - C5-437|
J. Phys. Colloques 48 (1987) C5-435-C5-437
QUASI-BOUND STATES IN AN ASYMMETRIC GaAs-AlAs SUPERLATTICEJ. SINGLETON1, R.J. NICHOLAS1, N.J. PULSFORD1, N.R. COUCH2 et M. J. KELLY2
1 The Clarendon Laboratory, Parks Road, GB-Oxford 0X1 3PU, Great-Britain
2 GEC Research Limited, Hirst Research Centre, East Lane, GB-Wembley HA9 7PP, Middlesex, Great-Britain
Interband photoconductivity measurements have been performed on a "Quasi-Graded-Gap" Superlattice (QGGSL). A number of features, both sharp and broad, are observed in the photoresponse, corresponding to transitions between the quasi-bound states of the superlattice. These features are described by a calculation, within an envelope-function approximation, of the pseudo-stationary states of the QGGSL. It is found that the electrons chiefly tunnel through the barriers in the device via states associated with the X-conduction band minimum of AlAs. The calculation also shows that the emission lines seen in electroluminescence spectra are due to recombinations between electrons and light holes, as the light holes tunnel through the QGGSL much more readily.