Journal Article

Origin of passivation in hole-selective transition metal oxides for crystalline silicon heterojunction solar cells

Alcubilla, Ramón, Puigdollers, Joaquim, Voz, Cristobal, Gerling, Luis G.

2017

Overview

Transition metal oxides (TMOs) have recently demonstrated to be a good alternative to boron/phosphorous doped layers in crystalline silicon heterojunction solar cells. In this work, the interface between n-type c-Si (n-Si) and three thermally evaporated TMOs (MoO3, WO3, and V2O5) was investigated by transmission electron microscopy, secondary ion-mass, and x-ray photoelectron spectroscopy. For the oxides studied, surface passivation of n-Si was attributed to an ultra-thin (1.9–2.8 nm) SiO x∼1.5 interlayer formed by chemical reaction, leaving oxygen-deficient species (MoO, WO2, and VO2) as by-products. Carrier selectivity was also inferred from the inversion layer induced on the n-Si surface, a result of Fermi level alignment between two materials with dissimilar electrochemical potentials (work function difference Δϕ ≥ 1 eV). Therefore, the hole-selective and passivating functionality of these TMOs, in addition to their ambient temperature processing, could prove an effective means to lower the cost and simplify solar cell processing.

• Publisher: Cambridge University Press,Springer International Publishing,Springer Nature B.V
• Subject: Ambient temperature / Applied and Technical Physics / Biomaterials / Byproducts / Chemical reactions / Crystal structure / Dissimilar materials / Fermi surfaces / Heterojunctions / Inorganic Chemistry / Interfaces / Interlayers / Invited Paper / Invited Papers / Materials Engineering / Materials research / Materials Science / Metal oxides / Nanotechnology / Passivation / Passivity / Photoelectrons / Photovoltaic cells / Selectivity / Silicon / Silicon wafers / Solar cells / Spectrum analysis / Transition metal oxides / Tungsten oxides / Work functions / X ray photoelectron spectroscopy