High quality non-rectifying contact of ITO with both Ni and n-type GaAs

We report the specific contact resistance for ITO with both metal and a semiconductor. Good quality ITO was deposited by electron beam evaporation with the resistivity of 2.32 x 10(-4) Omega.cm and an averaged transmittance of 92.8% in the visible light region. The circular transmission line model (c-TLM) method was used to evaluate and compare the properties of the ITO/metal and ITO/semiconductor ohmic contacts. The lowest specific contact resistance of the ITO/Ni is 2.81 x 10(-6) Omega.cm(2), while that of ITO/n-GaAs is 7 x 10(-5) Omega.cm(2). This is the best ohmic contact between ITO and n-GaAs ever reported. These results suggest that good quality ITO has strong potential to be used to realize highly efficient solar cells.