  We used first-principles calculations to investigate the laterally stitched
monolayered MoSi2N4/XSi2N4 (X=W, Ti) 2D heterostructures. The structural
stability of such heterostructures is confirmed by the phonon spectra
exhibiting no negative frequencies. From the electronic band structures, the
MoSi2N4/WSi2N4-lateral heterostructure (MWLH) shows semiconducting nature with
an indirect bandgap of 2.35 eV, while the MoSi2N4/TiSi2N4-lateral
heterostructure (MTLH) revealed metallic behavior. Moreover, the effect of
biaxial strain on the electronic and optical properties of MWLH is studied,
which indicated substantial modifications in their electronic and optical
spectra. In particular, an indirect to direct bandgap semiconducting transition
can be achieved in MWLH via compressive strain. Besides, the absorbance,
transmittance and reflectance spectra can effectively be tuned by means of
biaxial strain. Our findings provide insights into the strain engineering of
electronic and optical features, which could pave the way for future nano- and
optoelectronic applications.
