Study of electrical behavior of metal-semiconductor contacts on exfoliated MoS₂ flakes

While 2D materials have been investigated for their potential applications in nanoelectronic and optoelectronic devices, their functionality is still not fully explored due to lack of proper understanding of metal contacts on these materials. The present work pertains to the study of electrical behavior of different metals such as chromium, silver, nickel, and platinum deposited on to exfoliated MoS₂ flakes. Comparative study of different metal contacts to MoS₂ shows that Ag/Au exhibits good ohmic behavior with high current injection efficiency and better linearity and symmetry of I-V curves than Cr/Au and Ni/Au contacts. Specific contact resistivity is measured to be 4.54 x 10^-4 Ω cm² using transmission line measurement (TLM) for Ag/MoS₂ contacts. Further, taking Ag/Au as ohmic contact, Pt/MoS₂ Schottky barrier diode is fabricated with a high rectification ratio of about 900. Barrier height and ideality factor of 0.56 and 2.1 eV, respectively are obtained. This study opens up the possibility of having high quality metal contacts on MoS₂ with potential applications in nanoscale devices. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)