In this study, Ge（1-x）Snx alloy films are co-sputtered on Si（100） substrates using RF magnetron sputtering at different substrate temperatures. Scanning electron micrographs, atomic force microscopy（AFM）, Raman ...In this study, Ge（1-x）Snx alloy films are co-sputtered on Si（100） substrates using RF magnetron sputtering at different substrate temperatures. Scanning electron micrographs, atomic force microscopy（AFM）, Raman spectroscopy, and x-ray photoemission spectroscopy（XPS） are conducted to investigate the effect of substrate temperature on the structural and optical properties of grown Ge Sn alloy films. AFM results show that RMS surface roughness of the films increases from 1.02 to 2.30 nm when raising the substrate temperature. This increase could be due to Sn surface segregation that occurs when raising the substrate temperature. Raman spectra exhibits the lowest FWHM value and highest phonon intensity for a film sputtered at 140℃. The spectra show that decreasing the deposition temperature to 140℃ improves the crystalline quality of the alloy films and increases nanocrystalline phase formation. The results of Raman spectra and XPS confirm Ge–Sn bond formation. The optoelectronic characteristics of fabricated metal-semiconductor-metal photodetectors on sputtered samples at room temperature（RT） and 140℃ are studied in the dark and under illumination. The sample sputtered at 140℃ performs better than the RT sputtered sample.展开更多
基金Project supported by the Universiti Sains Malaysia(Grant No.1001/PFIZIK/846072)
文摘In this study, Ge（1-x）Snx alloy films are co-sputtered on Si（100） substrates using RF magnetron sputtering at different substrate temperatures. Scanning electron micrographs, atomic force microscopy（AFM）, Raman spectroscopy, and x-ray photoemission spectroscopy（XPS） are conducted to investigate the effect of substrate temperature on the structural and optical properties of grown Ge Sn alloy films. AFM results show that RMS surface roughness of the films increases from 1.02 to 2.30 nm when raising the substrate temperature. This increase could be due to Sn surface segregation that occurs when raising the substrate temperature. Raman spectra exhibits the lowest FWHM value and highest phonon intensity for a film sputtered at 140℃. The spectra show that decreasing the deposition temperature to 140℃ improves the crystalline quality of the alloy films and increases nanocrystalline phase formation. The results of Raman spectra and XPS confirm Ge–Sn bond formation. The optoelectronic characteristics of fabricated metal-semiconductor-metal photodetectors on sputtered samples at room temperature（RT） and 140℃ are studied in the dark and under illumination. The sample sputtered at 140℃ performs better than the RT sputtered sample.
