Energy band alignment of an In2O3:: Mo/Si heterostructure

A novel transparent conductive film In2O3: Mo (IMO) was sputtered onto a Si wafer, and the energy band alignment at the IMO/Si interface was studied. A large built-in potential (V-d = 1.77 eV) was detected by capacitance-voltage (C-V) measurement, and the schematic band alignment of IMO/p-Si was plotted. The conduction and valence band offsets have been deduced as Delta E-c = 0.86 eV and Delta E-v = 1.62 eV, respectively. The current-voltage (I-V) measurements show rectifying characteristic for IMO/p-Si and ohmic contact for IMO/n-Si. Reverse current-temperature (I-0-T) measurements gave an activation energy E-ac = 0.23 eV, which represents the transition from the top energy level in a narrow and deep well to the conduction band of IMO. The measurement of a photocurrent spectrum showed signals of three discrete levels in the narrow potential well, and the energy value of the transition from the top level to IMO (0.17-0.23 eV) agrees well with the E-ac obtained by the I-0-T measurement.