An analytical model of dark saturation current of silicon solar cell considering both SRH and Auger recombination
An analytical model of dark saturation current of silicon solar cell considering both SRH and Auger recombination
复制标题
考虑SRH和俄歇复合的硅太阳能电池暗饱和电流分析模型
DOI：
10.1109/rsm.2011.6088280
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Md. Iqbal Bahar Chowdhury
中科院分区：
文献类型：
--
作者：
S. Saha;A. M. Farhan;S. I. Reba;S. I. Ferdaus;Md. Iqbal Bahar Chowdhury
太阳能电池的暗饱和电流的分析建模传统地结合SRH（Schokley-Reed-Hall）复合或俄歇复合，因为同时考虑这两种机制导致数学复杂性。另一方面，在实际的太阳能电池中使用了非均匀掺杂分布，其中引入了延迟电场，并且因此降低了暗饱和电流。此外，掺杂水平日益增加，以满足太阳能电池性能提高的要求。然而，重掺杂水平以及掺杂分布的不均匀性导致载流子迁移率的位置和场依赖性，并且还导致载流子寿命的掺杂依赖性。此外，在这样的重掺杂水平下，带隙变窄效应也变得显著。这种后一种效应导致暗饱和电流的延迟电场减小，因此增加了暗饱和电流。因此，所有这些影响应纳入现代太阳能电池的暗饱和电流的分析建模。然而，考虑所有这些影响，特别是同时考虑SRH和俄歇复合机制导致的控制方程的二阶，非线性，变系数微分方程，因此，导致微分方程是解析棘手的。本文利用指数逼近技术解决了这一解析难题，该技术可以逼近任何指数型分布（高斯分布、互补误差函数等）。或任何掺杂相关的传输参数（迁移率、寿命等）。一个简单的指数函数。因此，该技术可用于任何掺杂水平和任意掺杂分布。所开发的模型表明，由于同时考虑SRH和俄歇复合的暗饱和电流的变化变得显着相比，考虑任何一个复合机制。模型结果还表明，考虑到这两种复合机制的暗饱和电流的变化随掺杂水平的增加。
The analytical modeling of dark saturation current of a solar cell conventionally incorporates either SRH (Schokley-Reed-Hall) recombination or Auger recombination, since simultaneous consideration of both these mechanisms results in mathematical complexity. On the other hand, non-uniform doping profile is used in the practical solar cells for which a retarding electric field is introduced and as a result, the dark saturation current is reduced. Moreover, the doping level increases day by day to meet the requirements for the improvement of solar cell performances. However, the heavy doping level as well as the non-uniformity of the doping profile lead to the position and field dependency of the carrier mobility and also, to the doping dependency of the carrier lifetime. Moreover, the bandgap narrowing effects also become significant at such heavy doping levels. This later effect causes the retarding electric field for the dark saturation current to reduce and hence, increases the dark saturation current. Therefore, all these effects should be incorporated in the analytical modeling of the dark saturation current of modern solar cells. However, consideration of all these effects especially simultaneous consideration of both SRH and Auger recombination mechanisms leads the governing equation to a second order, nonlinear, variable-coefficient differential equation and hence, causes the differential equation to be analytically intractable. In this paper, the analytical intractability problem has been resolved by using an exponential approximation technique, which can approximate any exponential-like profile (Gaussian, complementary error function etc.) or any doping dependent transport parameter (mobility, lifetime etc.) into a simple exponential function. Therefore, this technique can be used for any doping level and for arbitrary doping profile. The developed model shows that the changes in the dark saturation current due to the simultaneous consideration of SRH and Auger recombination becomes significant compared to the consideration of any one recombination mechanism. The model results also show that the change in the dark saturation current considering both recombination mechanisms increases with the doping level.