Polycrystalline Ge1-xSnx（poly-Ge1-xSnx） alloy thin films with high Sn content（〉 10%） were fabricated by cosputtering amorphous GeSna-GeSn on Ge100 wafers and subsequently pulsed laser annealing with laser energy ...Polycrystalline Ge1-xSnx（poly-Ge1-xSnx） alloy thin films with high Sn content（〉 10%） were fabricated by cosputtering amorphous GeSna-GeSn on Ge100 wafers and subsequently pulsed laser annealing with laser energy density in the range of 250 mJ/cm^2 to 550 mJ/cm^2. High quality poly-crystal Ge0.90 Sn0.10 and Ge0.82 Sn0.18 films with average grain sizes of 94 nm and 54 nm were obtained, respectively. Sn segregation at the grain boundaries makes Sn content in the poly-GeSn alloys slightly less than that in the corresponding primary a-GeSn. The crystalline grain size is reduced with the increase of the laser energy density or higher Sn content in the primary a-GeSn films due to the booming of nucleation numbers. The Raman peak shift of Ge-Ge mode in the poly crystalline GeSn can be attributed to Sn substitution, strain,and disorder. The dependence of Raman peak shift of the Ge-Ge mode caused by strain and disorder in GeSn films on full-width at half-maximum（FWHM） is well quantified by a linear relationship, which provides an effective method to evaluate the quality of poly-Ge1-xSnx by Raman spectra.展开更多
Hafnium disulfide(HfS2) is a promising two-dimensional material for scaling electronic devices due to its higher carrier mobility, in which the combination of two-dimensional materials with traditional semiconductors ...Hafnium disulfide(HfS2) is a promising two-dimensional material for scaling electronic devices due to its higher carrier mobility, in which the combination of two-dimensional materials with traditional semiconductors in the framework of CMOS-compatible technology is necessary. We reported on the deposition of HfS2 nanocrystals by remote plasma enhanced atomic layer deposition at low temperature using Hf(N(CH3)(C2H5))4 and H2S as the reaction precursors. Selflimiting reaction behavior was observed at the deposition temperatures ranging from 150℃ to 350℃, and the film thickness increased linearly with the growth cycles. The uniform HfS2 nanocrystal thin films were obtained with the size of nanocrystal grain up to 27 nm. It was demonstrated that higher deposition temperature could enlarge the grain size and improve the HfS2 crystallinity, while causing crystallization of the mixed HfO2 above 450℃. These results suggested that atomic layer deposition is a low-temperature route to synthesize high quality HfS2 nanocrystals for electronic device or electrochemical applications.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61474094)the National Basic Research Program of China(Grant No.2013CB632103)
文摘Polycrystalline Ge1-xSnx（poly-Ge1-xSnx） alloy thin films with high Sn content（〉 10%） were fabricated by cosputtering amorphous GeSna-GeSn on Ge100 wafers and subsequently pulsed laser annealing with laser energy density in the range of 250 mJ/cm^2 to 550 mJ/cm^2. High quality poly-crystal Ge0.90 Sn0.10 and Ge0.82 Sn0.18 films with average grain sizes of 94 nm and 54 nm were obtained, respectively. Sn segregation at the grain boundaries makes Sn content in the poly-GeSn alloys slightly less than that in the corresponding primary a-GeSn. The crystalline grain size is reduced with the increase of the laser energy density or higher Sn content in the primary a-GeSn films due to the booming of nucleation numbers. The Raman peak shift of Ge-Ge mode in the poly crystalline GeSn can be attributed to Sn substitution, strain,and disorder. The dependence of Raman peak shift of the Ge-Ge mode caused by strain and disorder in GeSn films on full-width at half-maximum（FWHM） is well quantified by a linear relationship, which provides an effective method to evaluate the quality of poly-Ge1-xSnx by Raman spectra.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFB2200103)。
文摘Hafnium disulfide(HfS2) is a promising two-dimensional material for scaling electronic devices due to its higher carrier mobility, in which the combination of two-dimensional materials with traditional semiconductors in the framework of CMOS-compatible technology is necessary. We reported on the deposition of HfS2 nanocrystals by remote plasma enhanced atomic layer deposition at low temperature using Hf(N(CH3)(C2H5))4 and H2S as the reaction precursors. Selflimiting reaction behavior was observed at the deposition temperatures ranging from 150℃ to 350℃, and the film thickness increased linearly with the growth cycles. The uniform HfS2 nanocrystal thin films were obtained with the size of nanocrystal grain up to 27 nm. It was demonstrated that higher deposition temperature could enlarge the grain size and improve the HfS2 crystallinity, while causing crystallization of the mixed HfO2 above 450℃. These results suggested that atomic layer deposition is a low-temperature route to synthesize high quality HfS2 nanocrystals for electronic device or electrochemical applications.
