薄膜太阳能电池在不同偏压下的量子效率(QE)会呈现非常不一样的结果.对不同波长范围内偏压量子效率的分析可以研究薄膜太阳能电池窗口层区域杂质补偿情况、主结势垒高低、背势垒高度等，还可以得出耗尽区宽度以及少子扩散长度等重要参数.通过实验测量与理论分析，给出了薄膜太阳能电池耗尽区宽度(W)和少子扩散长度(Ln)与偏压量子效率的关系，提出了一种新的拟合耗尽区宽度(W)和少子扩散长度(Ln)的方法，探讨了偏压量子效率测试在薄膜太阳能电池特性分析中的应用.

Quantum efficiency measured at different voltage varies in a wide range. Compensation of the window layer, quality of the main junction and the value of back contact barrier can be derived from the voltage dependent quantum efficiency at different wavelength region. Depletion width and diffusion length of the minority carrier can be calculated from the apparent quantum efficiency. Relationship of the depletion width, diffusion length of the minority carrier and apparent quantum efficiency is presented in the article. A new method to calculate the depletion width and diffusion length of the minority carrier is proposed. Furthermore, we discussed the feasibility of studying thin film solar cells via its voltage dependent quantum efficiency.