| Summary: | 碩士 === 南台科技大學 === 機械工程系 === 101 === In this research, we study synthesized of tin (II) sulfide (SnS) by investigating the orthorhombic and zinc blende phase using thermal decomposition method. The experimental procedures were divided into three fabrication processes:
1) Tin oxide (SnO) and oleic acid (OA) were used to synthesis precursor and tin-oleate complexes precursor, Sn(OA)2 was obtained after purification of the precursor. Sn(OA)2, oleylamine and sulfur powder(1-9 mmol) were used to synthesis tin (II) sulfide (SnS) nanocrystals at different temperatures under argon atmosphere. In this experiment, crystal size of about2 μmsheet structureoftin sulfide is obtained.
2) Sn(OA)x, was directly injected into OLA-S (oleylamine-sulfur solution) without purification of the of tin-oleate complexes precursor and hold at different temperature 130 °C - 310 °C to synthesis SnS nanocrystals. The experimental results indicated that at low temperature, irregular shape of SnS and particle size of about 20 ~ 50 nm is obtained. At high reaction temperature, hexagonal columnar SnS will grow along the preferred (101) plane with diameter of about 200 ~ 250 nm.
3) The Sn(OA)x precursor was added into manganese oxide (MnO) (0%-30%) to synthesis the Sn1-xMnx(OA)x precursor. Sn1-xMnx(OA)x precursor and hold at different temperature (130 °C - 290 °C) was then injected into OLA-S (oleylamine-sulfur solution) to synthesis zinc blende and orthorhombic phase SnS nanocrystals. The results indicated with 10% of MnO under reaction temperature of 260 °C, zinc blende SnS and orthorhombic SnS are obtained. When the reaction temperature was further increased to 290 °C, SnS zinc blende phase is completely transformed into orthorhombic phase. However, when 30% of MnO was added under reaction temperature at 260 °C, SnS will remain zinc blende phase as the main phase.
The properties of zinc blende and orthorhombic SnS were investigated using optical properties analysis and magnetic analysis. UV-vis analysis showed that SnS orthorhombic phase has a strong absorption at 980 nm with direct and indirect band gap of 1.25 eV and 1.24 eV, respectively. Therefore, SnS orthorhombic phase is expected to be a direct band gap semiconductor. Moreover, SnS zinc blende phase has a strong absorption at 840 nm with direct and indirect band gap of 1.61 eV and 1.26 eV, respectively. Thus, SnS zinc blende phase is expected to be an indirect band gap semiconductor. Superconducting Quantum Interference Device Magnetometer (SQUID) was used to investigate the magnetic changes of zinc blende phase and orthorhombic phase. The results showed that the paramagnetic orthorhombic phase transfer to ferromagnetic at temperature of 225K, while zinc blende phase was superparamagnetic material.
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