Measurement of Optical Properties of Infrared Bandgap Superlattices.

摘要

The lattice-matched bandgap-tunable heterostructure system Ga(x)In(1-x)As(y)P(1-y)/InP is technologically important because the bandgap can be tuned with composition between 1.55 and 0.90 um wavelengths. Because the range of bandgaps in this heterostructure system is further into the infrared when compared to the much studied GaAs/Ga(x)Al(1-x)As system, many spectroscopic techniques are more difficult. For example, prior to this study no inelastic light scattering had been done in this heterostructure system for laser wavelengths longer than the InP bandgap wavelength, that is, in a region where resonant interaction with the confined states of the wells is possible and where four polarization combinations of incident and scattered light are possible (rather than only two when backscattering is done at an opaque wavelength). Utilizing this technique was one of the primary goals of this project. A second goal was to attempt to clarify a confusing situation in this heterostructure system in which previous photoluminescence measurement gave huge discrepancies with predicted emission photon energies of between 50 and 200 meV. This contrasted sharply with the GaAs/GaAlAs system in which agreement was in 1 to 2 meV range.... Superlattices, Infrared Bandgap Superlattices, Heterostructures, Laser Diodes, Photodetector Diodes.