Silicon/organic hybrid heterojunction infrared photodetector operating in the telecom regime

Abstract

The authors report on the fabrication of a silicon/organic heterojunction based IR photodetector. It is demonstrated that an Al/p-Si/perylene-derivative/Al heterostructure exhibits a photovoltaic effect up to 2.7μm (0.46eV), a value significantly lower than the bandgap of either material. Although the devices are not optimized, at room temperature a rise time of 300ns, a responsivity of ≈0.2mA/W with a specific detectivity of D∗≈7×107 Jones at 1.55μm is found. The achieved responsivity is two orders of magnitude higher compared to our previous efforts [1,2]. It will be outlined that the photocurrent originates from an absorption mechanism involving excitation of an electron from the Si valence band into the extended LUMO state in the perylene-derivative, with possible participation of intermediate localized surface state in the organic material.The non-invasive deposition of the organic interlayer onto the Si results in compatibility with the CMOS process, making the presented approach a potential alternative to all inorganic device concepts.