Determination of band offsets in AlGaAs/GaAs and InGaAs/GaAs multiple quantum wells
The determination of valence band offsets Q/sub v/ by fitting the optical transmission spectra for Al/sub x/Ga/sub 1-//sub x/As/GaAs and In/sub y/Ga/sub 1-//sub y/As/GaAs multiple quantum wells (MQWs) is discussed. The valence band offset Q/sub v/ is defined as Q/sub v/ = ..delta..E/sub v//(..delta..E/sub v/+..delta..E/sub c/), where ..delta..E/sub v/ and ..delta..E/sub c/ are the valence and conduction band discontinuities at the heterojunction. For Al/sub x/Ga/sub 1-//sub x/As/GaAs (Type I for both heavy holes and light holes, i.e., electrons, heavy holes, and light holes are located in the same layers) the energy separation ..delta..E between the first light and heavy hole subbands in the valence band is used to determine the valence-band offset Q/sub v/. In order to improve the precision, MQWs with narrow well widths and higher Al mole fraction x should be used. Further, the inclusion of coupling between the valence and conduction subbands in Kane's three-band model is also essential. However, Q/sub v/ is still not determined uniquely by the above energy difference ..delta..E. Different combinations of Q/sub v/ and heavy hole effective masses m/sub h//sub h/ in GaAs can lead to the same ..delta..E. The forbidden transition E/sub 13//sub h/ in a narrow well can be used to identify the actual values of m/sub h//sub h/ and Q/sub v/.
- Research Organization:
- Coordinated Science Laboratory, University of Illinois at Urbana, Urbana, Illinois 61801
- OSTI ID:
- 6196405
- Journal Information:
- J. Vac. Sci. Technol., B; (United States), Journal Name: J. Vac. Sci. Technol., B; (United States) Vol. 5:5; ISSN JVTBD
- Country of Publication:
- United States
- Language:
- English
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