n-GaAs diode with photoresponsivity based on 3-aminorhodanine thin films

In this paper, the electrical characteristics of a 3-aminorhodanine (aRh)/n-gallium arsenide (n-GaAs) heterostructure were investigated in dark and under various illumination conditions. Although the structure shows a low rectifying rate, the photocurrent in both the forward and reverse biasing increases with increasing illumination intensity. The photodiode exhibits a large detectivity (the capability of detecting visible light), approaching 3.9×10¹¹ Jones at room temperature. On illumination with light (100  mW/cm²), the current value in the aRh/n-GaAs heterostructure is 2.8×10⁵ times, when compared to its dark value at zero applied voltage. The obtained responsivity value at the bias of 2 V and under the illumination intensity of 100  mW/cm² is 0.16 A/W, which is high for any organic-inorganic hybrid photodiode. The photocurrent-to-dark-current ratio is 6.5×10⁴. Results show that an aRh/n-GaAs self-powered photodiode introduces new opportunities for dynamic systems needing partially low or zero external energy inputs.