H_2Se气体硒化中温度对CIGS吸收层特性的影响

INFLUENCE OF TEMPERATURE ON THE PROPERTIES OF CIGS ABSORBING LAYERS IN H_2Se SELENIZATION PROCESS

采用H_2Se气体对铜-铟-镓金属预制层进行硒化制备铜铟镓硒(CIGS)光吸收层,研究硒化过程中温度对CIGS结晶质量及光学特性的影响。400~500℃单一温度硒化制作的CIGS薄膜的表面平整性较差,存在颗粒状聚集物。在硒化前引入200℃低温预处理过程,可提高CIGS薄膜表面的平整性和致密性。在400℃硒化后导入500℃高温热处理过程可提高CIGS的结晶质量并改善Ga元素掺入的均匀性。光学特性测量显示,优化硒化温度可降低CIGS薄膜的缺陷态,从而提高Ga元素在薄膜中的掺入效果,CIGS薄膜的光学带隙可达1.14 e V。利用CIGS薄膜制备的太阳电池光电转换效率达13.1%,开压为519 m V,有效面积为0.38 cm^2。

We study the influence of temperature on the structural and optical properties of CIGS layers in H2Se gas selenization process for Cu-In-Ga precursor layer, It was found that a simple one-step selenization at 400-500 ℃ results in rough surface morphology with bulge granules. A pre-treatment at low temperature of 200 ℃ before the selenization at 400 ℃ helps to improve the flatness and compactness, and a high-temperature annealing at 500 ℃after the pre-treatment at 200 ℃ and selenization at 400 ℃ further improves the crystalline and optical properties of CIGS layers. Optical measurements showed that the optical absorption induced by defect states reduces and the substitution of Ga is enhanced by optimizing the temperature flow chat. The optical band gap of CIGS is 1.14 eV. A CIGS solar cell based on the selenized CIGS layer is fabricated and a conversion efficiency of 13.1% and open-circuit voltage of 519 mV are achieved on a 0.38 cm2 active area.