In search of a hole inversion layer in $\mathrm{Pd}/\mathrm{MoO}_{x}/\mathrm{Si}$ diodes through I- V characterization using dedicated ring-shaped test structures

Palladium (Pd) capped molybdenum-oxide $(\mathrm{MoO}_{x})$ thin films deposited bye-beam evaporation on p- and n-type silicon (Si) substrates were investigated employing dedicated ring-shaped test structures. The results show diode characteristics on n-type Si with a high rectification of $\sim 10^{8}$ and a low leakage current of $\sim \pmb{10}^{-11}$ A and an ohmic contact on p-type Si, as expected from the reported high workfunction of $\mathbf{MoO}_{x}$. Reports in the literature that an inversion layer of holes should be present at the $\mathbf{MoO}_{x}/\mathbf{n}$ -Si interface were investigated via various DC electrical measurements on lateral test structures, but no indication of any sianificant inversion was found.