Insights into CrS2 monolayer and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si6.svg"><mml:mi>n</mml:mi></mml:math>-CrS2/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si7.svg"><mml:mi>p</mml:mi></mml:math>-HfN2 interface for low-power digital and analog nanoelectronics

• CrS 2 monolayer (ML) exhibits properties superior to MoS 2 , WS 2 . • n -CrS 2 / p -HfN 2 van der Waals heterobilayer (vdWH) forms a pn -heterojunction. • Weaker vertical E-field (VEF) closes the band gap in the vdWH relative to CrS 2 -ML. • Weak VEF induces ambipolar spin transport properties. • CrS 2 -ML and CrS 2 based vdWH show great potential in futuristic nano-electronics. CrS 2 monolayers exhibit excellent mechanical, electronic, piezoelectric and thermal properties as compared to other well-known transition metal dichalcogenides. CrS 2 /HfN 2 van der Waals heterobilayer (vdWH) forms a pn -heterojunction where CrS 2 and HfN 2 act as an n -type and p -type semiconductor respectively, thereby suggesting its utility in nano-electronics and photodetectors. The perpendicular electric field is effective in manipulating band alignments and band gap in CrS 2 /HfN 2 vdWH. Weaker electric field is able to close the band gap in the vdWH relative to CrS 2 ML. Therefore, the vdWH may be a promising candidate in low-power analog and digital nano-electronics. Vertical electric field is found to drive the nearly free electron gas (NFEG) states to near the Fermi level in CrS 2 ML. These surface states, reported in a few low-dimensional materials, will enhance charge transport and conductivity in electronics. Furthermore, the combined effect of spin–orbit coupling and a small magnitude of vertical electric field helps to reach a type-II band alignment in the CrS 2 /HfN 2 vdWH. It unusually shows a large spin splitting at both conduction and valence band edges, which is very crucial for ambipolar spin transport. This work demonstrates possibilities for futuristic nano-electronic devices based on CrS 2 ML & CrS 2 based vdWH.