Band‐to‐Band Tunneling Control by External Forces: A Key Principle and Applications

Abstract

Band‐to‐band tunneling (BTBT) devices with superior subthreshold swing directly related to on/off switching speed and power consumption efficiency have emerged as a breakthrough of the limitation in conventional metal‐oxide‐semiconductor field‐effect transistors (MOSFETs). However, it is difficult to reach a higher level of electrical characteristics with only a combination of materials based on their intrinsic characteristics. External forces, such as electric fields, light, and temperature, can modulate the electron and hole concentration and control the tunneling probability and the electrical characteristics of heterostructure electronics. Recent articles employing external forces to improve the BTBT performance and demonstrate the mechanism of BTBT devices are summarized with five representative external forces. Moreover, the utility of the external force‐induced performance improvement of the BTBT device is also discussed by providing various applications.

Porous crystalline materials for memories and neuromorphic computing systems

“…368 In a type III p-n heterojunction, the proximity of the conduction band (CB) in the n-type region to the VB in the p-type region facilitates electron tunneling from VB to CB via BTBT process. 368 As a result, the BTBT process generates high-energy electrons ( i.e. , band-to-band hot electrons, BBHE) that can be trapped by the FG layer.…”

“…Band-to-band tunneling (BTBT) provides an alternative explanation for the programming/erasing process of flash memory, which is quantum tunneling in essence rather than thermionic transportation, and takes place in flash memory with type III heterojunction. 368 In a type III p-n heterojunction, the proximity of the conduction band (CB) in the n-type region to the VB in the p-type region facilitates electron tunneling from VB to CB via BTBT process. 368 As a result, the BTBT process generates high-energy electrons (i.e., band-to-band hot electrons, BBHE) that can be trapped by the FG layer.…”

“…368 In a type III p-n heterojunction, the proximity of the conduction band (CB) in the n-type region to the VB in the p-type region facilitates electron tunneling from VB to CB via BTBT process. 368 As a result, the BTBT process generates high-energy electrons (i.e., band-to-band hot electrons, BBHE) that can be trapped by the FG layer. This process overcomes the fundamental thermionic limitation of SS (60 mV dec À1 ) and effectively enhances carrier injection rate, resulting in steep turn-on characteristics.…”

“…Developing flash memory devices with high operating speed is significant for massive data storage. Various approaches, including constructing vdWs heterostructure, 280,376 utilizing BTBT mechanism, 368,370 and optimizing the device structure, [377][378][379] have been employed to achieve high performance memory devices with ultrafast operating speed. Owing to the excellent porosity, structural/composition designability, and film formation capacities, the porous crystalline materials can be developed for forming high-quality films or vdWs heterostructures with superior charge trapping ability.…”

Room Temperature Negative Differential Resistance with High Peak Current in MoS2/WSe2 Heterostructures

“…3 NDR devices are based on the transition of carrier transport from quantum mechanical tunnelling to thermionic emission by sweeping the applied voltage. 4 To use NDR for functional devices, the output characteristics of the transistor in the NDR regime should have a high peak current (I peak ) and a high peakto-valley current ratio (PVCR). The importance of high I peak and high PVCR lies in their role in enabling efficient signal amplification, reliable switching behavior, and optimization of device performance for various high-frequency applications.…”