Pentacene/n−-Si heterojunction diodes and photovoltaic devices investigated by I–V and C–V measurements

The forward and reverse current density–voltage (J–V) and capacitance–voltage (C–V) characteristics of pentacene/n−-silicon heterojunction diodes were investigated to clarify the carrier conduction mechanism at the organic/inorganic heterojunction. Current rectification characteristics of the pentacene/n−-Si junctions can be explained by a Schottky diode model with an interfacial layer. The diode parameters such as Schottky barrier height and ideality factor were estimated to be 0.79–1.0 eV and 2.4–2.7, respectively. The C–V analysis suggests that the depletion layer appears selectively in the n−-Si layer with a thickness of 1.47 μm from the junction with zero bias and the diffusion potential was estimated at 0.30 eV at the open-circuit condition. The present heterojunction allows the photovoltaic operation with power conversion efficiencies up to 0.044% with a simulated solar light exposure of 100 mW/cm2.

Current density–voltage characteristics of pentacene/n-Si heterojunction.Figure optionsDownload as PowerPoint slide