Effect of additional HfO₂ layer deposition on heterojunction c‐Si solar cells

Abstract

Abstract The efficiency of a heterojunction with intrinsic thin‐layer ( HIT ) solar cell with an insulator/ ITO structure was discussed in this paper. First, the efficiency was analyzed by OPAL 2 simulations. Second, an insulator/ ITO structure was experimentally applied to a HIT solar cell. The OPAL 2 simulations using an insulator/ ITO /Si structure and a TCO / ITO /Si structure showed that the generation current density in the Si substrate increased when the insulator or TCO layer had a proper thickness. Experimentally, HfO 2, a type of insulator, was deposited on a HIT solar cell with a thickness varying from 3 to 15 nm. The average efficiency of the HIT solar cell improved from 18.21% to 20.75% after HfO 2 deposition. The highest efficiency was achieved for the 3‐nm‐thick HfO 2 / HIT solar cell structure, which exhibited the best improvement in the current density of approximately 1.5 mA /cm 2 . For the external quantum efficiency of the HfO 2 / HIT solar cell, the total absorption was improved by HfO 2 deposition. The results suggest that the HfO 2 layer improves the solar cell efficiency of the HIT solar cell by increasing light absorption.