Fabrication of Visible-Light-Transparent Solar Cells Using p-Type NiO Films by Low Oxygen Fraction Reactive RF Sputtering Deposition

Abstract

Visible-light-transparent p-type NiO films were deposited by reactive RF sputtering under unintentional heating. An optical transmittance of >80% was obtained in the wavelength range of 500–800 nm when the films were deposited under a very low O2 fraction in the gas phase O2/(Ar+ O2) = 0.5%. This result may reflect a decrease in the concentration of Ni vacancies due to the increase in their formation energy under oxygen-poor deposition conditions. Heterostructure pn junctions consisting of p-type NiO and n-type ZnO layers were also deposited. We eventually observed a slight but noticeable photovoltaic effect.

Experimental determination of band offsets of NiO-based thin film heterojunctions

“…It is noted that representative NiO films showed an optical transmittance of more than 80%. 23 The optical transmittance in the near-infrared region (1200-2000 nm) decreased because of plasma oscillations of the ITO layer. The observed interference effect demonstrates that the film is reasonably flat.…”

“…Details on the deposition of NiO layer are available elsewhere. 23 One of several n-type layers (i.e., ZnO, Mg 0.3 Zn 0.7 O, amorphous Zn 0.5 Sn 0.5 O, ITO, SnO 2 , or TiO 2 ) was deposited with a thickness of approximately 50 nm by RF sputtering onto a NiO film to form a heterojunction.…”

Fabrication of visible‐light transparent solar cells composed of NiO/NixZn1‐xO/ZnO heterostructures

“…Additionally, they have the advantage of absorbing only UV light, which is harmful to humans. For example, Tsai et al reported a NiO/ZnO nanowire-based heterojunction structure for application in photovoltaic devices [18], Rhee et al reported Cu 2 S/NiO solar cells and obtained a NiO layer by annealing NiO powder at 650 °C for 60 min [19], and we also have fabricated NiO/ZnO solar cell by RF reactive sputtering without intentional heating in a previous study [20]. However, the demonstrated efficiency of such cells remains low.…”

“…The fraction of O 2 in the sputtering gas [O 2 /(Ar + O 2 )] was varied from 0 to 10%. Additional details on the deposition of NiO layer are available elsewhere [20]. A p-type NiO layer was deposited by RF sputtering onto a NiZnO film to form a heterojunction.…”

Investigation of the sulfurization process of Cu2SnS3 thin films and estimation of band offsets of Cu2SnS3‐related solar cell structure

“…However, issues associated with fabrication/material costs and safety remain unresolved. In terms of material design for compound semiconductors, the most cost-effective, safe, and easily handled anions are sulfur and oxygen [2][3][4]. Ternary chalcogenide compound, Cu 2 SnS 3 (CTS), is a promising candidate as an earth-abundant absorber material [5].…”