Effects of atom doping on the electronic and magnetic properties of BAs/WSe2 heterostructure

Van der Waals heterostructures formed by stacking two different semiconductor monolayers develop rapidly and exhibit very unique and diverse physical properties. With the implementation of first principles calculations based on density functional theory (DFT), we investigate the effect of single-atom doping of Al, Ga, C, N, O, F, P, S and Cl and double oxygen atoms doping on the structural, electronic and magnetic properties of BAs/WSe2 heterostructure. The results illustrate that the Al, Ga, N and P atom-doped systems, which are grouped with B or As atoms, essentially maintain the direct band gap width of the pristine system, while the F and Cl single-atom doped systems open the band gaps of 0.118 and 0.153 eV, respectively. Single and double oxygen atoms doped systems except zigzag 0-1 system exhibit magnetic properties. Moreover, the magnetic moment of the double oxygen atoms doped systems is about twice as large as that of the O single atom doped system. In particular, the armchair 0-3 system opens a band gap of 87 meV compared to the single-atom doped system, with the VBM contributed by spin up states and the CBM occupied by spin down states. By analyzing the absorption spectra, we found that both the pristine BAs/WSe2 system and the doped system have excellent optical absorption in a wide range of ultraviolet and visible light. In particular, the four doped systems Al, Ga, N and P and the pristine BAs/ Se2 system have a direct band gap and type I band alignment, which can be applied to electronic devices such as laser emitters (LE) and light emitting diodes (LEDs). Our investigation provides a robust theoretical basis for the application of single-atom doped BAs/WSe2 heterostructures in future optoelectronic devices such as LE, LEDs and photodetector devices.