Abstract: A method and an apparatus which permits use of a metal-insulator-semiconductor device as an infrared detector. A single layer of metal is provided having an extremely thin portion through which infrared radiation can pass and a thick portion through which infrared radiation cannot pass. Both of these portions together form the MIS (metal-insulator-semiconductor) gate. A voltage is applied to the metal which creates a potential well within the semiconductor substrate below. When the device is exposed to infrared radiation the radiation, causes photons to pass through the thin portion of the MIS gate and generates a charge within the potential well. The thick portion of the MIS gate shields the semiconductor substrate from photons so that no charges are generated in the potential well which is located below this portion of the metal layer. This provides a charge storage region so that the charge which is generated under the thin gate can be stored in the entire potential well created by the gate as a whole.