Noise and electrical transport properties of polycrystalline InSb thin films

Abstract

Both noise and electrical transport properties of polycrystalline InSb thin films are measured and analyzed for the same potential model. Films are prepared by evaporation upon sputtered SiO2 glass and annealed in an Ar atmosphere. Films are inhomogeneously compensated and show what appears to be p- and n-type conduction at low temperatures. It is found that the n-type films actually contain p-n junctions because the measured barrier heights reach the energy of the band gap. Between 150 and 77°K, low conducting sheets along grain boundaries with notch-type barriers exist. Current noise of 1/f type observed at room temperature is well correlated with this notch-type barrier. A higher notch-type barrier leads to lower mobility as well as higher noise voltage. This indicates that the noise originates in the bulk effect of the films.