| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 90 === The optical properties of InxGa1-xAs1-yNy films have been studied using photoreflectance (PR), peizoreflectance (PzR) and surface phovoltage (SPV) measurements. Several interband transition features are observed. According to the band anticrossing model these features are attributed to the E－, E－+D0, and E+ transitions, respectively. The transition energies E－and E－+D0 shift to lower energy with increasing In and N concentrations, while the splitting between E－ and E+ increases with N content. The temperature dependence of the transition energies E－ and E－+D0 has been studied in terms of both the Varshni and Bose-Einstein equations. The parameters that describe the temperature variation of E－ and E－+D0 transitions are evaluated and discussed. In addition, above the GaAs bandgap, clear Franz-Keldysh oscillations (FKOs) in the PR spectra of the InxGa1-xAs1-yNy films are observed in the temperature range between 30 and 300 K. The appearance of FKOs at low temperature might indicate the existence of the piezoelectric field between InxGa1-xAs1-yNy/GaAs interfaces.
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