Room-temperature self-powered energy photodetector based on optically induced Seebeck effect in Cd3As2

We demonstrate an intrinsically fast Seebeck-type metal-semimetal-metal infrared photodetector based on Cd3As2 crystals. The Seebeck voltage is induced under off-center illumination, leading to asymmetric temperature gradients and a net current flow. The room-temperature responsivity of the sensor is 0.27mA/W. The photocurrent signal is readily registered at a modulation frequency of 6 kHz, and the intrinsic bandwidth of the sensor is predicted to approach the terahertz range. The photocurrent depends on the optical power and modulation frequency. Our study demonstrates that crystalline Cd3As2 is a promising material for high-bandwidth and spectrally broad photosensing, imaging, and communication. (C) 2017 The Japan Society of Applied Physics