Determination of External Quantum Efficiency for Graphene-based Photodiode

Abstract

In this study, we aimed to investigate the electrical properties of graphene-based photodiode coated by drop casting and spin coating methods. We have deposited graphene onto n-type Si wafers via drop casting and spin coating methods. Spin coating was performed at 1500 rpm for 40 seconds. Both devices were dealt with 100 °C temperature. Metallic contacts were formed by depositing 150 nm Al via physical vapor deposition. To investigate photodiode properties, FY7000 Solar Simulator was used for current-transient (I-t) measurements. Responsivity and external quantum efficiency (EQE) of both devices were obtained using Visible hard-coated bandpass filter kits with typically 10 nm FWHM supplied from Thorlabs GmbH (Germany). EQE and responsivity of drop casted device were found to be higher than spin coated one.