A design for a high-sensitivity photodetector with a single layer of MoS2 transition-metal dichalcogenide used as the basic functional element is proposed and the process of its fabrication is presented step by step. Quality evaluation and the selection of functional MoS2 flakes is based on the results of combined optical characterization. The main operating characteristics of the fabricated device are investigated and a photosensitivity of 1.4 mA/W is demonstrated. A difference of this device in comparison with existing analogues is its high photosensitivity at low operating voltages (in the range of ±3 V).