Abstract: A thermal-radiation imaging device comprises at least one semconductor body portion (10,20,30,40), e.g. of n-type cadmium mercury telluride, on which biasing-electrode means (1 to 4 and 4b to 44b), e.g. of gold, are spaced for causing a bias current predominantly of majority charge-carriers to flow along each strip (10,20,30,40). The bias current supports an ambipolar drift of radiation-generated charge carriers in the opposite direction. One or more read-out means (e.g. 11,21,51,41) is present in the drift path of each body portion (e.g. 10). The body portion (10,20,30,40) is present on a substrate 100 having a conductor pattern (61 to 64, 71 to 74, 81 to 84, 91 to 94) which provides electrical connections to each of the read-out means. Each read-out means which may be a diode junction or an electrode pair is formed at holes (reference a and b for an electrode pair) which extend through the thickness of the body portion (10,20,30,40) to the conductor pattern of the substrate (100).

Abstract: In the manufacture of an infrared radiation detector device, a body of p-type cadmium mercury telluride is bombarded with ions to etch away a part of the body. From the etched-away part of the body an excess concentration of mercury is produced which acts as a dopant source converting an adjacent part of the body into n-type material. The energy of the bombarding ions is less than 30 keV. By appropriately choosing the ion dose this conversion from p-type to n-type can be effected over a depth considerably greater than the penetration depth of the ions. A p-n junction can be fabricated in this way for a photovoltaic detector. The conductivity type conversion may even be effected through the body thickness. The etching and conversion can be localized by masking part of the body surface against the ion bombardment.