In-plane anisotropic photoelectric property of α-In2Se3 based phototransistor

Contributing to excellent photoelectric property, the tunable bandgap and intercorrelated in-plane and out-of-plane ferroelectric polarization simultaneously, α-In2Se3 has great potential in the applications of optoelectronic devices and photo-controlled devices, like memories, sensors, and synapses. However, little attention is paid to the in-plane anisotropic photoelectric property of α-In2Se3, which may restrict its competitiveness in application of designing and fabrication of optoelectronic devices and photo-controlled devices. Herein, multi-layered α-In2Se3 based phototransistors with eight terminals are prepared, and its in-plane anisotropic photodetection is investigated. By comparing the dark current (Idark), photocurrent (Iph), responsivity (R), external quantum efficiency (EQE), and specific detectivity (D*), in-plane anisotropic photoelectric property of multi-layered α-In2Se3 is demonstrated, and the Idark, Iph, R, EQE, and D* anisotropic ratios are up to 163.76, 480.59, 480.59, 480.59, and 58.8, respectively. The carrier mobility and the in-plane ferroelectric polarization are the two main factors determining the in-plane anisotropic photoelectric property. The excellent in-plane anisotropic photoelectric property makes α-In2Se3 a promising candidate as an in-plane anisotropic semiconductor for high-sensitivity optoelectronic and photo-controlled applications.