Abstract: The heterojunction diodes of n-type nanocrystalline silicon on p-type crystalline silicon were fabricated and electrically characterized. The nanocrystalline silicon layer (nc-Si:H) was deposited in a plasma enhanced chemical vapor deposition system. Electrical properties were investigated by capacitance-voltage and current-voltage measurements at different temperature.The capacitance-voltage results confirm that it is an abrupt heterojunction. Current-voltage characteristics show good temperature stability and good rectifying properties. Two carrier transport mechanisms are believed to be the origin of the forward current. At low bias voltage (V<0.8 V), the current is determined by recombination at the nanocrystalline side of the space charge region. The bending of band reduces the bandgap of the nanocrystalline silicon layer and, therefore, the activation energy for the recombination process. It is the main reason for the good temperature stability of the heterojunction. While, at higher bias voltages (V>1.0 V), the current becomes space charge limited.