Non-ohmic hopping conduction in Ge nanocrystalline film

Temperature-dependent transport properties of Ge nanocrystalline films (nanofilms) prepared by the cluster beam evaporation technique have been studied. The nanofilms of thicknesses about View the MathML source, deposited on the substrates at room temperature, exhibit non-linear current–voltage characteristics in the low bias range with decreasing temperature. In order to understand the conduction via the grain boundaries between two adjacent Ge nanocrystals, the temperature-dependent conductivity of the nanofilms has also been investigated, which could be explained by Mottʹs variable range hopping mechanism between 100 and View the MathML source. Below View the MathML source, the conductivity is limited by ordinary tunneling of carriers giving rise to temperature-independent behavior.