Creating Novel Transport Properties in Electric Double Layer Field Effect Transistors Based on Layered Materials

Abstract

We present a study on the liquid/solid interface, which can be electrostatically doped to a high carrier density (n~10 14 cm -2 ) by electric-double-layer gating. Using micro-cleavage technique on the layered materials: ZrNCl and graphene, atomically flat channel surfaces can be easily prepared. Intrinsic high carrier density transport regime is accessed at the channel interface of electric double-layer field effect transistor, where novel transport properties are unveiled as the field-induced superconductivity on the ZrNCl with high transition temperature at 15 K, and accessing a high carrier density up to 2×10 14 cm -2 in graphene and its multi-layers. INTRODUCTIONTransport through ultra-thin layered materials is fruitfully manipulated by the field effect. Especially, at the low carrier density (n~10 12 cm -2 ) regime, it witnesses the exciting new physics originated from unusual chiral particles in graphene, an archetypal example in the layeredmaterial based transistors. Inspired by the material abundance, and richness variations in their properties on the carrier density, In this research, we aim at studying the transport properties in layered materials with extended carrier concentration, especially in the less explored higher density regime, utilizing the electrochemical principle of electric double layer formed at a liquid/solid interfaces.These liquid/solid interfaces are widely used in applications in catalytic activities and energy storage [1, 2], they are also important for the novel electronic functions in electric double layer transistors (EDLTs) exemplified by high performance organic electronics [3][4][5][6][7], fieldinduced electronic phase transitions [8][9][10][11], as well as superconductivity in SrTiO 3 [12]. Broadening EDLT to creating novel transport properties within other materials is highly demanded for enriching material science. However, it is severely hampered by inadequate choice of materials and processing techniques [13]. Whereas, in layered materials, special advantage exist as high quality surface could be easily prepared by cleavage. Here we introduce an effective method using ionic liquids as gate dielectrics, mechanical micro-cleavage techniques for surface preparation, and report the observation of field-induced superconductivity showing T c = 15.2 K on an atomically flat film of layered nitride compound, ZrNCl. And large amount of carriers could also be induced on other materials such as graphene and its multi-layers to a value of 2×10 14 using similar techniques. The present result reveals that the EDLT is an extremely versatile technique to induce electronic phase transitions by electrostatic charge accumulation

Graphene-Based Light Sensing: Fabrication, Characterisation, Physical Properties and Performance

“…Sometimes encapsulation is necessary due to the environmental instability of some of the constituent materials. This is usually achieved by depositing a polymer layer on top, such as Poly-methyl-methacrylate (PMMA), or by using an ionic liquid [ 24 , 25 , 26 ] such as lithium perchlorate-PEO (LiClO -PEO) which also acts as a gating electrode [ 27 , 28 ].…”