氟掺杂氧化锡薄膜电活性缺陷密度的太赫兹谱探测

从理论上分析了电场应力前后氟掺杂氧化锡（FTO）薄膜的能带结构和传导机理，提取了应力前后FTO薄膜的太赫兹电导率。采用Drude模型对应力前的FTO薄膜太赫兹（THz）电导进行了仿真；采用了Hopping模型对应力后的THz电导进行了仿真，实验与仿真结果一致。结果表明，应力后FTO的电导率提高了3个数量级，源于电场作用下的粒子内作用电导和粒子间作用（陷阱辅助隧穿）电导。通过适合的电导仿真模型，可以清楚地区分出陷阱辅助隧穿电导，从而提取FTO薄膜的陷阱密度。研究结果为利用太赫兹光谱提取半导体薄膜缺陷密度提供了一种便捷的新方法。

DETECTION ON ELECTROACTIVE TRAP DENSITY OF FTO FILM BY THz CONDUCTIVITY SPECTRUM

The band structure and conduction mechanism of fluorine-doped tin oxide (FTO) film before and after electric field stress were analyzed theoretically. The terahertz conductivity of FTO film before and after electric field stress was extracted. The THz conductance of FTO film before stress was simulated by the Drude model. Hopping model was adopted to simulate THz conductance after stress. The experiment results agreed with the simulation results very well. The results showed that the conductivity of FTO was increased three orders after stress, which was due to the intra-particle interaction conductance and inter-particle interaction (trap-assisted tunneling) conductance under electric field. Based on the suitable simulation model, the trap assisted tunneling conductance could be clearly distinguished, and the trap density of FTO film could be obtained. The results provide a new and convenient method for extracting the trap density of semiconductor thin filmby terahertz spectrum.