VEMT Silicon NPN Phototransistors Vishay Semiconductors VEMT Silicon NPN Phototransistors are silicon NPN epitaxial planar phototransistors in a miniature surface-mount package (SMD) with a dome lens. The VEMT2003X01, VEMT2023X01, and VEMT2023SLX01 modules include a daylight filter that is matched with 830nm to 950nm IR emitters. The VEMT2503X01, VEMT2523X01, and VEMT2523SLX01 variants are sensitive to visible and near-infrared radiation. Applications for Vishay Semiconductors VEMT Silicon NPN Phototransistors include automotive, miniature switches, light sensors, and more.