Graphene/SOI-based self-powered Schottky barrier photodiode array

Abstract

We have fabricated a four-element graphene/silicon on insulator (SOI) based Schottky barrier photodiode array (PDA) and investigated its optoelectronic device performance. In our device design, monolayer graphene is utilized as a common electrode on a lithographically defined linear array of n-type Si channels on a SOI substrate. As revealed by wavelength resolved photocurrent spectroscopy measurements, each element in the PDA structure exhibited a maximum spectral responsivity of around 0.1 A/W under a self-powered operational mode. Time-dependent photocurrent spectroscopy measurements showed excellent photocurrent reversibility of the device with ∼1.36 and ∼1.27 μs rise time and fall time, respectively. Each element in the array displayed an average specific detectivity of around 1.3 × 1012 Jones and a substantially small noise equivalent power of ∼0.14 pW/Hz-1/2. The study presented here is expected to offer exciting opportunities in terms of high value-added graphene/Si based PDA device applications such as multi-wavelength light measurement, level metering, high-speed photometry, and position/motion detection.