Desenvolvimento de transistores de efeito de campo a partir de monocamada de WS2 sobre hBN em substrato de óxido de silício

Abstract

The discovery of graphene triggered a significant increase in research related to two-dimensional materials. Among them, transition metal dichalcogenides, 2D materials referring to groups 4-7 of the periodic table with layers made up of covalent bonds between the transition metal and the dichalcogen with hexagonal packing. Tungsten disulfide (WS2) has the characteristic, in the format of a single atomic layer, a direct gap between conduction and valence bands with values close to 2 eV. As it is a semiconductor material, WS2 can be used in some applications, such as electronic devices. One of them, essential for electronic equipment such as computer motherboards and chips, is the field effect transistor. Its mode of operation is to regulate the electrical current that passes between 2 terminals, called drain and source, using the controlling variable, the electrical voltage at one of its terminals called gate. The main objectives of this work were the manufacture of field effect transistors using WS2 on an insulating material with few atomic layers, hexagonal boron nitride (hBN), on a silicon substrate with deposited silicon oxide, using beam lithography. electrons, and their electrical characterization. Furthermore, it was also an objective to use non-destructive methods to characterize WS2, such as photoluminescence and Raman spectroscopy. At the end of the characterizations, they were compared with different bibliographies to attest to the viability of this methodology and the functioning of the manufactured transistors.