An Anti-Ambipolar Cryo-Phototransistor

Novel anti-ambipolar transistors (AATs) are gate tunable rectifiers with a marked potential for multi-valued logic circuits. In this work, the optoelectronic applications of AATs in cryogenic conditions are studied, of which the AAT devices consist of vertically stacked p-SnS and n- MoSe2 nanoflakes to form a type-II staggered band alignment. An electrostatically tunable p-SnS/n-MoSe2 cryo-phototransistor is presented with unique anti-ambipolar characteristics and cryogenic-enhanced optoelectronic performance. The cryo-phototransistor exhibits a sharp and highly symmetric anti-ambipolar transfer curve at 77 K with the peak-to-valley ratio of 103 operating under a low bias voltage of 1 V. The high cooling-enhanced charge mobilities in the cryo-phototransistor grant this AAT device remarkable photodetection capabilities. At 77 K, the p-SnS/n-MoSe2 cryo-phototransistor, holding a broad photoresponse in the spectral range of 250−900 nm, demonstrates its high responsivity of 2 × 104 A W−1 and detectivity of 7.5 × 1013 Jones with the excitation at 532 nm. The high-performance p-SnS/n-MoSe2 low-dimensional phototransistor with low operating voltages at 77−150 K is eligible for optoelectronic applications in cryogenic environments. Furthermore, the cryo-characteristics of this heterostructure can be further extended to design the mul-tivalued logic circuits operated in cryogenic conditions.