Simulation investigation of strained black phosphorus photodetector for middle infrared range

In this paper, we design the uniaxially and biaxially strained black phosphorus (BP) photodetectors. Different strains applied in the zigzag or armchair direction can effectively tune the direct band gap of 5-layer of BP. The optical field intensity is modeled to determine the absorption for the BP layer. The strain effect on the band structure of BP is investigated using first-principles method based on density functional theory. The cut-off wavelength of strained 5-layer of BP pin photodetector is extended to middle infrared range with a high responsivity of 66.29 A/W, which means that the strained black phosphorus photodetector provides a new approach for the middle-infrared range optoelectronic devices.