Thickness-dependent bandgap engineering of multi-layer 2D molybdenum disulfide

Because of the dependence of bandgap on the layer number and accordingly the thickness of MoS 2 , here we numerically investigate the optical gain profile and efficiency of solar energy harvesting of the multi-layer Molybdenum Disulfide acting as the optical amplifier and solar cell. The ability to tune the bandgap of semiconductors for optoelectronic and photovoltaic technologies, traditionally achieved through compositional or strained engineering in bulk semiconductor materials, is realized through the change of thickness. We conclude that the dependence of optical gain spectra can be varied by the thickness, and moreover by considering the competition between carrier transport and light absorption, the optimized layer number with maximum power conversion efficiency can be obtained. • Demonstrate thickness-dependent bandgap engineering in multi-layer MoS 2 for tunable optoelectronics. • Predict the maximum optical gain and threshold injection current density for a tri-layer MoS 2 double-heterostructural optical amplifier. • Identify six-layer MoS 2 can achieve the highest simulated power conversion efficiency for photovoltaic devices. • Highlight the potential usage of 2D MoS 2 for next-generation renewable energy systems.