Band modulation and optoelectronic properties of 2D Janus Ge2SeTe/Sn2SSe van der Waals heterostructures

Two-dimensional (2D) van der Waals heterostructures (vdWHs) demonstrate outstanding capabilities in conceiving electronic and optoelectronic devices. Here, we construct Ge2SeTe/Sn2SSe vdWHs and investigate their electronic structures and optoelectronic properties under the influence of different interface characteristics, interlayer coupling, strain and electric field. The results show that the interface stacking patterns can obviously affect the band gap values of the vdWHs, and broad optical absorption spectrum can be realized from visible to the ultraviolet region. Additionally, interlayer coupling, biaxial strain or electric field can transform the band alignment of the vdWHs between type I and type II. Interestingly, the Se–S interface vdWHs have high power conversion efficiency (∼21.16%). Our works demonstrate that 2D Janus Ge2SeTe/Sn2SSe vdWHs have promising applications in optoelectronic devices.