Title: Optical characterization of synthetic diamond films
Abstract: Synthetic diamond films grown by vapor-phase growth have attracted much interest because of promising applications in electronic devices. Improvement of film quality by reducing the number of crystal defects and impurities is the most important prerequisite for successful device applications. Defects and impurities produce deep states in the wide band gap of diamond. These mid-gap states decrease the efficiency of edge emission and exhibit `visible' luminescence. Recently, it has become possible to obtain high-quality diamond films that show phonon-assisted exciton recombination radiation from the indirect edge. The analysis of edge emission spectra can be used to characterize crystallinity and purity of synthetic diamond films. We have studied band edge structure of synthetic diamond films of differential reflectance spectroscopy as well as cathodoluminescence. The differential reflectance spectrum obtained from a high-pressure-high-temperature synthetic diamond shows interband transitions assisted by phonon emission. On the other hand, chemical vapor deposited diamond films show a zero-phonon exciton transition together with the phase-assisted transitions. This indicates light absorption by bound excitons due to crystal defects. Furthermore, we have investigated higher interband transitions localized in the Brillouin zone by a newly developed electron-beam electroreflectance spectroscopy.
Publication Year: 2000
Publication Date: 2000-11-29
Language: en
Type: article
Indexed In: ['crossref']
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