稳态光电压测量技术

给出稳态光电压测量方法的原理图，比较MIS模式与夹层模式得到的SPV信号，结合光电流响应的测量，以金红石型TiO2（001）面单晶表面为研究对象，可以看出夹层模式与MIS模式得到的光电压结果近似，夹层模式具有更高的灵敏度，结合弱场诱导夹层模式能够给出更多的亚带隙跃迁的信息，而外加电场对光电流和MIS模式测得的光电压没有影响．同时比较有无弱场存在时的SPV与光电流信号，探讨了弱场诱导的可能作用机理．亚带隙跃迁得到的光电压具有与高于带隙宽度的光电压响应不同的产生机制和电荷分离模式。

Steady-State Surface Photovoltage Technique

Combined with the equivalent circuit diagram and principle sketch map of steady-state SPV measurement, the SPV values of c-axis TiO2 single crystal are estimated and compared with the value estimated from photocurrent measurement. The SPV values are obtained by the sandwich SPV measurement model and the MIS SPV measurement model. The experiment shows that the sandwich SPV measurement model is similar to MIS SPV measurement model and has higher sensitivity. Furthermore, the sandwich model can provide sub-gap transition SPV information when biasing a weak dc field. And the weak dc field is of no effect on MIS model SPV and photocurrent signal, The weak dc field works in localized state transition and can not affect delocalized transition. On the other hand, the sub-gap transition SPV has different carrier separating mechanism from super-gap transition SPV.