High Mobility Hafnium and Hydrogen Co-Doped Indium Oxide Transparent Conductive Films and Application in High Efficiency Silicon Heterojunction Solar Cell

Abstract

In this work, high quality hafnium and hydrogen co-doped In O (IHfO:H) transparent conductive films are developed via a reactive plasma deposition (RPD) technique followed by air atmosphere annealing. Crystallinity, valence states, and opto-electronic properties of the IHfO:H films under different H concentration (0-1.5 %) and different annealing temperature (100-250 °C) are systematically investigated. The effects of hydrogen doping and annealing temperature on the properties of the IHfO:H films are discussed. The high average transmittances (400-800 nm: 87.92 %; 800-2300 nm: 86.68 %), a sheet resistance of 27.53 Ω/□, and a Hall mobility of 102.92 cm V s are achieved on the optimized IHfO:H thin film fabricated using 0.8 % H concentration with a 200 °C annealing temperature. Finally, the IHfO:H films are applied to the bifacial silicon heterojunction (SHJ) solar cells to serve as the front-side transparent electrode. The significant improvement in the long wavelength spectral response compared to the control SHJ device with an indium tin oxide (ITO) front-side transparent electrode leads to an increase of about 0.3 % in the efficiency and an efficiency of over 25 % is achieved on the SHJ solar cell with an IHfO:H front-side transparent electrode.