Ti掺杂ZnTe体材料的优化光致发光光谱

Optimal photoluminescence spectrum from Ti-doped ZnTe

针对光致发光光谱法研究ZnTe :Ti的困难 ,对包括激发能量、激发功率与激发光斑大小、水汽干扰和测量温度等实验条件进行了细致的优化 .发现 :(1)低于ZnTe禁带宽度的激发能量能给出相对强的光致发光光谱 ;(2 )水汽干扰既影响谱线的相对强度又增大谱线能量的测定误差 ;(3)相对强的激光聚焦有利于获得较好的光致发光光谱 .可靠地观察到位于 390 3.5和 390 5 .9cm- 1 能量位置处的零声子光致发光谱线 .根据两谱线的能量间距和相对强度随温度的变化关系 ,并借助于晶体场理论对四面体晶体场中 3d1 和 3d2 杂质离子能级的分析 ,该零声子光致发光谱线被界定为源于Ti3+ 的深能级跃迁 ,从而获得了Ti3+ 存在于Ⅱ

In this paper, experimental conditions are carefully optimized of excitation energy, power and degree of focus, water disturbance and temperature to overcome the difficulties involved in photoluminescence (PL) study of ZnTe:Ti. It is illustrated that: (i) Higher PL intensity is accessible with excitation energy just below the band-gap energy of ZnTe. ( ii) Water disturbance not only changes the relative intensities of the PL lines but also increases the measuring error of the transition energies. NO Excitation with relatively stronger focus produces better PL spectrum. Two zero-phonon lines (ZPLs) are unambiguously identified at 3903.5 and 3905.9 cm(-1), respectively. They are ascribed to be due to Ti3+ in ZnTe with the aid of the crystal field theory I the transition energy, the energy difference of the two ZPLs and the temperature dependence of the relative intensity of the ZPLs. It is the first evidence from PL study for the Ti3+ in II - VI compound semiconductors.