Magnetospectroscopy of Donor States in Gallium Arsenide/aluminum Gallium Arsenide Quantum Wells
Abstract
High-resolution far-infrared (FIR) laser magneto -optical studies of donor states in GaAs/AlGaAs quantum wells are presented here. These studies were performed utilizing a photoconductivity technique which, although standard for bulk semiconductor studies, has only very recently been successfully applied to studies of semiconductor quantum wells. The data presented here is the highest resolution and signal-to-noise donor magnetospectroscopic data yet reported for quantum wells. The spectroscopy experiments have included: (1) thorough studies of the 1s to 2p _{+1} transition in 510, 280, and 170 A quantum wells; (2) a discovered discrepancy between the theory and experiment for these transitions in narrow wells; (3) a complete study and first observation of the tilt-induced anticrossing of two "2p-like" states in a quantum well; (4) the first definitive evidence for the presence of D^- states in a quantum well; (5) the first probable observation of the, usually forbidden, 1s to 2s transition in a quantum well; (6) the observation of several other, currently unidentified, transitions. Further, wherever possible, extensive descriptions and derivations of relevant theory are included. Preliminary work on detector applications of these quantum well samples is also presented. This work has concentrated on utilizing nonlinearities in their response for the coherent detection of FIR radiation. This thesis includes fairly complete descriptions of the operation of optically-pumped FIR laser systems, cryogenic detectors, superconducting magnets, and Hall probes. Detailed descriptions of the procedures followed in the data acquisition and analysis programs are also presented.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- January 1992
- Bibcode:
- 1992PhDT.......101M
- Keywords:
-
- GALLIUM ARSENIDE/ALUMINUM GALLIUM ARSENIDE;
- Physics: Condensed Matter; Physics: Electricity and Magnetism