常见点缺陷对硅光电池响应特性的影响

Effect of Common Point Defects in Silicon Cells on Device Response Characteristics

摘要:

研究了硅光电池中常见点缺陷对器件在激光辐照下的响应特性的影响。根据第一性原理建立了晶胞模型,比较了空位缺陷以及含Fe,Cu杂质状态下硅材料的态密度图,在此基础上分析了常见点缺陷对硅光电池响应特性的影响。由于半导体材料对温度敏感,当光电池受激光辐照而出现温度变化时,其光电响应输出特性会发生变化。从光伏器件的光生电动势原理出发,根据响应输出模型以及一维热传导方程,计算了1064nm激光辐照下,空位和金属杂质两种本征点缺陷对光电池响应特性的影响规律。结果表明:空位和金属杂质两种缺陷都能够改变硅材料的能带结构和响应特性。当激光辐照波长为1064nm,功率密度为4×10⁵W/cm²时,其中间隙原子为Fe时对材料的电子结构和光学性质的影响最大。此时材料吸收系数高达23952cm-1,且量子效率值最大,导致光电池响应最为强烈,输出电压最小。

Abstract:

In this study, we investigated the effect of common point defects in silicon photocells on the response characteristics of devices under laser irradiation. We established a crystal cell model based on the first principles, compared the density of state values of silicon materials with Fe and Cu impurities, and analyzed the influence of common point defects on the response characteristics of silicon photocells. When the temperature of a photovoltaic cell changes after exposure to laser irradiation, its photoelectric response output characteristics alter owing to the sensitivity of a semiconductor material to temperature. Based on the principle of the light-generated electromotive force of a photovoltaic device, the response output model and one-dimensional thermal conduction equation were used to calculate the vacancy and impurity response characteristics under 1064nm laser irradiation. The results showed that both vacancies and metal impurities could change the band structure and response characteristics of silicon materials. Under a laser irradiation wavelength of 1064nm, the irradiation time was 1μs, and power density was 4×10⁵W/cm², where the gap atoms had the most dominant effects on the electronic structure and optical properties of the material. At this time, the absorption coefficient of the material was as high as 23952cm-1, and the quantum efficiency value was the largest, resulting in the strongest cell response and minimum output voltage.