InSe Schottky Diodes Based on Van Der Waals Contacts

Abstract

2D semiconductors are excellent candidates for next‐generation electronics and optoelectronics thanks to their electrical properties and strong light‐matter interaction. To fabricate devices with optimal electrical properties, it is crucial to have both high‐quality semiconducting crystals and ideal contacts at metal‐semiconductor interfaces. Thanks to the mechanical exfoliation of van der Waals crystals, atomically thin high‐quality single‐crystals can easily be obtained in a laboratory. However, conventional metal deposition techniques can introduce chemical disorder and metal‐induced mid‐gap states that induce Fermi level pinning and can degrade the metal‐semiconductor interfaces, resulting in poorly performing devices. In this article, the electrical contact characteristics of Au–InSe and graphite–InSe van der Waals contacts, obtained by stacking mechanically exfoliated InSe flakes onto pre‐patterned Au or graphite electrodes without the need for lithography or metal deposition is explored. The high quality of the metal‐semiconductor interfaces obtained by van der Waals contact allows to fabricate high‐quality Schottky diodes based on the Au–InSe Schottky barrier. The experimental observation indicates that the contact barrier at the graphite–InSe interface is negligible due to the similar electron affinity of InSe and graphite, while the Au–InSe interfaces are dominated by a large Schottky barrier.

Lowering the Contact Barriers of 2D Organic F16CuPc Field‐Effect Transistors by Introducing Van der Waals Contacts

“…On the one hand, atomic smooth and dangling‐bond free surfaces of both 2D metals and 2D OSCs result in clean hetero‐interfaces, suppressing the formation of mid‐gap states which are usually generated at evaporated metal/channel interface and resultant FLP at the hetero‐interface. [ 31–34 ] On the other hand, the huge family of 2D metals makes it more convenient to choose appropriate candidates as contact electrodes for 2D OFETs according to the band alignments of 2D metals and OSCs. [ 35,36 ] However, as far as we know, there lacks of relevant attempts to introduce vdW contacts with 2D metals as source–drain electrodes to realize efficient charge injection at the electrical contacts and the resultant improvement of electrical and optoelectronic performance of 2D OSCs.…”

Dependence of Photoresponsivity and On/Off Ratio on Quantum Dot Density in Quantum Dot Sensitized MoS2 Photodetector

“…We now study the nonlinear dependence of I ds on V ds using a Schottky junction model. The change from initial fast increase to a slow increase in I ds – V ds curve resembles the I – V characteristic of two back-to-back Schottky junctions [ 34 , 35 , 36 ]. Theoretically, I ds is limited by the reverse saturation current of Schottky junction when V ds is large.…”

Efficient ReSe2 Photodetectors with CVD Single-Crystal Graphene Contacts

“…At low bias (V bias < 1.5 V), the current limiting effect of the two Schottky barriers on the current is highlighted by the non-linear IV characteristic. For higher bias (~1.5 V < V bias < 2 V), the contacts appeared as non-blocking, with the current showing linear behavior [ 58 ]. The room temperature measurements at V bias = 2 V ( Figure 6 d) showed a photocurrent trend following two regimes: a supralinear behavior (marked by the red line) around a transition point, occurring at ND > 1, and an approximately linear trend (marked by the blue line) for ND < 1 (see also the inset).…”