2D nonlayered semiconductors attract intense interest due to their unique planar structure and various fascinating optoelectronic properties. Here, a method is developed to design orientation-controlled and well-defined single-crystalline PbS nanoplates arrays on mica. Furthermore, the single PbS nanoplate device displays great photoresponsivity, detectivity, and photogain values as high as 1621 A W , 1.72 × 10 Jones, and 2512, respectively.