High pressure sputtering of Mo targets in mixed Ar/O2/H2 atmospheres for hole selective contacts in photovoltaic cells

Abstract

We have deposited thin films of MoOx using highpressure

sputtering (HPS) and Ar/O2/H2 atmospheres aiming at

the compositional and interface control. We found that H2

impacts plasma composition, which in turn produces a

reduction of the oxygen content and a change in the refractive

index of the films. However, the presence of hydrogen in the

plasma atmosphere enhances interfacial SiOx regrowth, as

FTIR shows. TEM measurements show that this regrowth is not

critical for thin films. Also, increasing the hydrogen ratio

produces a change from amorphous to an

amorphous/polycrystalline mixture. Lifetime measurements

show that these films are adequate for their integration into test

HIT-like structures, but require more work to produce

competitive iVoc values.