Influence of hydrogen doping of In2O3-based transparent conducting oxide films on silicon heterojunction solar cells

Abstract

We report the influence of hydrogen doping of In2O3-based transparent conducting oxide (TCO) films, including indium tin oxide (ITO), hydrogenated ITO (ITO:H), In2O3 (IO), and hydrogenated In2O3 (IO:H), using radio-frequency magnetron sputtering for SHJ solar cells. The purpose of hydrogen doping is to improve the sheet resistance and work function, while Ar-based ITO films play a critical role in maintaining the electrical and optical properties. The thickness of all TCO films was fixed at 100 nm, which showed the lowest sheet resistance of 34 Ω/sq for the IO:H films. All the films showed an average transmission of more than 87% in the visible-wavelength (400–800 nm) region. The work function was enhanced from 4.96 to 5.45 eV with a hydrogen of 3 sccm. SHJ solar cells using IO:H films achieved an efficiency of 23.6% with an open-circuit voltage (VOC) of 736 mV, a current density (JSC) of 38.83 mA/cm2 and a fill factor (FF) of 82.62%. We performed an improvement in the conversion efficiency of the device with a simulation using the AFORS-HET (automatic for the simulation of heterostructures) program. The efficiency achieved was 25.41% when VOC = 729 mV, JSC = 41.3 mA/cm2, FF = 84.42%.