Electronic and optical properties of lateral heterostructures within monolayer black phosphorene and group-IV monochalcogenides

Two-dimensional lateral heterostructures (LHSs) exhibit novel electronic and optical properties, which provide new opportunities for optoelectronic devices. In this work, the energetic, electronic, and optical properties of monolayer LHSs of black phosphorene (BP) and group-IV monochalcogenides (GeS, GeSe, SnS, and SnSe) with armchair/zigzag interface are investigated by first-principles calculation. The results show that these heterostructures can exist stably via covalent bonds. These heterostructures show semiconducting properties except for the BP/SnSe heterostructure with zigzag interface, and their bandgaps can be tuned by the width of heterostructures. More importantly, these heterostructures possess wide optical absorption spectra and high adsorption coefficient. Moreover, the band offsets of heterostructures are calculated by the local density of states, which realize type-I, II, and III band alignments. Our results provide a systematical understanding of the properties of LHSs composed of black phosphorene and group-IV monochalcogenides, revealing their potential for photovoltaic applications.