Tunable electronic structure in stained two dimensional van der Waals g-C2N/XSe2 (X = Mo, W) heterostructures

The electronic structure of the strained g-C2N/XSe2 (X= Mo, W) van der Waals heterostructures are investigated by first-principles calculations. The g-C2N/MoSe2 heterostructure is an indirect band gap semiconductor at a strain from 0% to 8%, where its band gap is 0.66, 0.61, 0.73, 0.60 and 0.33 eV. At K point, the spin splitting is 186, 181, 39, 13 and 9 meV, respectively. For g-C2N/WSe2 heterostructures, the band gap is 0.32, 0.37, 0.42, 0.45 and 0.36 eV, and the conduction band minimum is shifted from Gamma-M region to K-Gamma region as the strain increases from 0% to 8%. Its spin splitting monotonically decreases as a strain raises to 8%, which is 445, 424, 261, 111 and 96 meV, respectively. Moreover, at a strain less than 4%, the conduction band mainly comes from g-C2N, but it comes from XSe2 (X= Mo, W) above 6%. Our results show that the g-C2N/XSe2 heterostructures have tunable electronic structures, which makes it a potential candidate for novel electronic devices.