Phase Modulators Based on High Mobility Ambipolar ReSe2 Field-Effect Transistors

Abstract

We fabricated ambipolar field-effect transistors (FETs) from multi-layered triclinic ReSe2, mechanically exfoliated onto a SiO2 layer grown on p-doped Si. In contrast to previous reports on thin layers (~2 to 3 layers), we extract field-effect carrier mobilities in excess of 102 cm2/Vs at room temperature in crystals with nearly ~10 atomic layers. These thicker FETs also show nearly zero threshold gate voltage for conduction and high ON to OFF current ratios when compared to the FETs built from thinner layers. We also demonstrate that it is possible to utilize this ambipolarity to fabricate logical elements or digital synthesizers. For instance, we demonstrate that one can produce simple, gate-voltage tunable phase modulators with the ability to shift the phase of the input signal by either 90° or nearly 180°. Given that it is possible to engineer these same elements with improved architectures, for example on h-BN in order to decrease the threshold gate voltage and increase the carrier mobilities, it is possible to improve their characteristics in order to engineer ultra-thin layered logic elements based on ReSe2.

The optical signature of few-layer ReSe2

“…1. Its anisotropic optical and electronic properties can be utilized to produce fieldeffect transistors [5][6][7] and photodetectors 8,9 . Moreover, it is reported that thin layer of ReSe 2 may be also used to fabricate ReS 2 /ReSe 2 heterojunction functioning as diodes or solar cells 10 .…”

Analog Circuit Applications Based on All‐2D Ambipolar ReSe2 Field‐Effect Transistors

“…Many interesting physical properties of ReSe 2 have been reported, such as layer‐dependent electrical and optoelectronic responses, polarized Raman spectroscopy, and polarization‐sensitive photoresponsivity . Recent studies have reported electron and hole mobilities as high as ≈10 2 cm 2 V −1 s −1 at low temperature and it shows potential as an alternative material to graphene for next‐generation circuits. However, there have been few studies to date on the electrical characteristics of this material, and a lack of investigations focused on its electronic device design.…”

A Library of Atomically Thin 2D Materials Featuring the Conductive‐Point Resistive Switching Phenomenon

“…[28] All other Raman spectra are consistent with previous reports. [29][30][31] In addition, other characterizations using photoluminescence for MoS 2 , MoSe 2 , WS 2 , and WSe 2 , and atomic force microscopy (AFM) for MoTe 2 are shown in Figures S1 and S2, Supporting Information, indicating high quality and uniformity, and offer complimentary validation of film thickness.…”