An Anti‐Ambipolar Cryo‐Phototransistor

Abstract

Abstract 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.

Keywords

• 2D materials
• anti‐ambipolar transistors
• low‐temperature electrical transport
• MoSe2
• photodetectors
• SnS