I-V and impedance characterization of a solution processed perovskite based heterojunction photodetector

Abstract

Herein, we report the investigation of electrical and photo response properties of hybrid organic-inorganic perovskite based photodetector. Surface morphology of perovskite thin film examined through Field emission scanning electron Microscope (FESEM) revealed smooth surface with complete coverage of the glass substrate. Different elements present in perovskite thin films, as well as their quantitative ratio are identified by Energy-dispersive X-ray spectroscopy (EDX) analysis. The current-voltage (I-V) measurements are carried out in dark and under illumination conditions to investigate the charge transport process and photodetector performance. The important diode electrical parameters (ideality factor, saturation current, and barrier height) are extracted by the analysis of I-V characteristics using Shockley model. The observed rectification and photo response behavior is analyzed using energy level diagram. The photodetector demonstrates good photoresponse and exhibits responsivity and detectivity value of 0.4 A/W and detectivity of 3 × 1011 Jones, respectively at -5 V. The charge transport mechanisms are examined under the framework of space charge limited conduction (SCLC) model, which helps to extract the mobility, trap density and trap energy. Moreover, electrochemical impedance spectroscopy (EIS) analysis is performed at different applied voltage and employed to determine the different device parameters such as recombination and charge transport resistance, chemical capacitance, mobility and life time. The mobility estimated from impedance analysis show good agreement with the mobility calculated from SCLC model.