Mixed‐Dimensional MoS₂/Ge Heterostructure Junction Field‐Effect Transistors for Logic Operation and Photodetection

Abstract

There has been a growing interest in electronic and optoelectronic devices based on heterostructures between atomically thin 2D and 3D semiconductor materials. This paper proposes a 2D molybdenum disulfide (MoS2)/3D germanium (Ge) junction field‐effect transistor (JFET). Typical electrical characteristics of the JFET are observed, with a low subthreshold swing of ≈88 mV/dec and a high on/off ratio of ≈105. The device exhibits a bidirection photoresponse in which the photocurrent polarity is reversed depending on the wavelength of light. Under visible illumination at 532 nm, the positive photoresponsivity of this device can be modulated by the gate voltage, reaching a peak value of 66 A W−1. In contrast, the device exhibits a tunable negative photoresponse behavior under an infrared illumination of 1550 nm. This is attributed to the competition between the negative photoresponse from the bolometric effect in MoS2 and the positive photoresponse from photogenerated carriers in Ge. Based on these interesting characteristics in this JFET, three controllable current states (−1, 0, and 1) are realized by changing the gate voltage and infrared light. These results indicate that the device has promising potential as a multifunctional optoelectronic unit, including signal amplification, broadband photodetection, and multilogic calculations.

Programmable WSe2/Ge Heterojunction Field‐Effect Transistor with Visible‐Infrared Wavelength‐Distinguishing Detection Capability

“…In recent years, the heterostructures between atomically thin 2D and 3D semiconductors have been gaining popularity. [33][34][35][36][37][38][39][40][41][42][43][44] The combination of 2D and 3D materials can capture the merits of both material systems to allow the design of high-performance electronic devices with unique functions. Besides, introducing 2D materials into the well-established 3D semiconductor fabrication processes can facilitate the development of 2D material applications.…”

Bidirectional Photoresponse in a Mixed-Dimensional MoS2/Ge Heterostructure and Its Optic-Neural Synaptic Behavior for Colored Pattern Recognition

“…More importantly, nearly zero hysteresis behavior can be observed (Δ V th < 0.1 V), which indicates that this HJFET is promising for reliable and accurate device operation owing to the consistent turn-ON/OFF voltage. Moreover, Figure f summarizes the SS value and supplied voltage of 2D-material-based JFET in recent years. − The relatively low SS value and supplied voltage of our HJFET are attractive for practical low power consumption applications …”

Review of Ge(GeSn) and InGaAs Avalanche Diodes Operating in the SWIR Spectral Region

“…By modulating the gate voltage, the device can reach a peak positive responsivity of 66 A/W under visible illumination at 532 nm. In contrast, the device exhibits a modifiable negative responsivity behavior under IR illumination at 1550 nm due to the combined effect of different polarity currents in MoS 2 and Ge ( Figure 26 ) [ 83 ]. These results provide a new strategy for the development of novel 2D/3D optoelectronic heterostructures that have good potential as multifunctional optoelectronic units.…”