Optical Characterization of Antimony-Based, Types-I and -II, Multiple Quantum-Well Semiconductor Structures for Mid-Infrared Laser Applications.

摘要

This experiment characterizes antimony-based, multiple quantum-well, types-I and -II, semiconductor samples designed for laser applications. The samples emit light in the 3-5-micron range to exploit an atmospheric transmission window, making them ideal for infrared (IR)-seeking missile countermeasures. Photoluminescence (PL) spectra were collected and yielded bandgap (E(sub g)) dependence-on-temperature relationships. The type-I sample was found to follow the Varshni equation, while the type-II samples showed a rise with temperature in a portion of the curve that should be linear according to the Varshni equation. The type-II samples followed the Varshni equation well at higher temperature. The PL study indicated that the type-I sample had better efficiency than the type-II samples, and that there is some change in efficiency with the waveguide nature of the sample. Carrier temperatures (T(sub c)) were derived from the PL study; all the samples for which Tc was derived operated in the optical phonon regime. The PL data were compared to the FEMB computer model and some correlation between the two in recombination energy was seen. A time- resolved photoluminescence (TRPL) experiment was conducted using the frequency upconversion technique. The experiment clearly found the upconverted signal, but there was a systematic error that prevented any further analysis of the data. (1 table, 27 figures, 30 refs.).