After depositing silicon-dioxide (SiO(2)) on a geranium (Ge) substrate at room temperature using a liquid-phase deposition (LPD) method fabricated metal-oxide-semiconductor (MOS) capacitors were used to extract the passivating properties of LPD-SiO(2) on the surface The procedure employed X-ray photoelectron spectroscopy current-voltage and capacitance-voltage measurements Our observation shows that (NH(4))(2)S treatment completely removes the native oxide (GeO(2)) from the Ge surface and passivate surface dangling bond Hence the (NH(4))(2)S treated MOS capacitor reveals a lower leakage current than an untreated capacitor by one order Different temperatures (200-400 C) for annealing were proposed to improve the passivating properties of LPD-SiO(2) With increasing annealing temperature fiat-band voltage shift fixed oxide-charge density and interface trap density significantly decrease Such a result indicates that the LPD-SiO(2) and (NH(4))(2)S treatment qualifies as a potential candidate in passivating the Ge substrate (c) 2010 Elsevier BV All rights reserved