【摘要】 利用高压原位角散X射线衍射实验研究了ZnSe纳米带的结构稳定性。发现样品在12.6 GPa附近存在一个从立方闪锌矿型到立方岩盐矿型的结构相变,并且在相变点附近存在较大的体积收缩,相对体积变化率达13%。利用Birch-Murnaghan状态方程拟合,得到了闪锌矿相的体弹模量约为56 GPa,略低于体材料的体弹模量(约67 GPa);并得到其立方岩盐矿相的体弹模量约为116 GPa。高压拉曼散射实验结果表明,横光学声子模散射峰在5.5 GPa压力附近发生劈裂,纵光学声子模散射峰在12.8 GPa压力以上逐渐消失。根据角散实验的体弹模量数据,计算得到了闪锌矿相中对应不同声子模式的格林爱森常数。更多还原

【Abstract】 Structural stability of ZnSe nanoribbons was analyzed by means of high-pressure in situ angular dispersive X-ray diffraction(ADXD).The pressure-induced structural transition from the Zinc blende(ZB) to a rocksalt(RS) phase occurs at about 12.6 GPa,and at the transition point the relative volume reduction is close to 13%.By fitting the relative volume-pressure relation to the Birch-Murnaghan equation of states,the bulk modulus B0 for the ZB and RS phases were determined.The values of B0 are 56 GPa(B′0=4) and 116 GPa(B′0=4) for the former and the latter,respectively.According to the measured high-pressure Raman scattering spectra,the TO phonon modes split into two peaks at about 5.5 GPa,and the LO peak gradually disappears above 12.8 GPa due to the semiconductor-metal transition.Using the value of the bulk modulus obtained from the ADXD experiments,the corresponding mode Grüneisen parameters are obtained for the ZB phase.更多还原