Determining height of a leaky Schottky barrier existing in the junction between SnO2 and a highly doped p-type amorphous SiC by using the pulsed laser-induced transient photopotential technique

The junction between SnO2 and a highly doped p-type amorphous SiC [a-SiC(p+)] is very important as a transparent contact to an a-Si alloy based solar cell. An energy-band diagram for this junction has been obtained here for the first time. A thin film of a-SiC(p+) deposited onto a SnO2-coated glass was immersed into a nonaqueous electrolyte solution and was irradiated with N2 laser pulses. The photopotential was monitored against a Ag reference electrode. The photopotential thus obtained showed that a leaky Schottky barrier exists at the SnO2/a-SiC(p+) junction. A band diagram was estimated, using an asymptotic value of the photopotential together with a position of the Fermi level calculated on the basis of the dark conductivity data.