Schneider, H.H.SchneiderWalther, MartinMartinWalther2022-03-082022-03-082004https://publica.fraunhofer.de/handle/publica/306512The semiconductor heterostructure IR radiation detector has an active layer comprising a periodic sequence of repeating individual layer systems, each of which has a potential well structure with one or more quantum wells with sub-bands forming an excitation zone which is joined at one side to a tunnel barrier zone with a potential, adjacent the excitation zone, which is higher than the band edge energy of a drift zone adjoining the other side of the potential well structure. The (a) the drift zone adjoins a capture zone which has one or more sub-band-containing quantum well structures and which is connected to the tunnel barrier zone of an immediately adjacent further individual layer system consisting of excitation, drift, capture and tunnel barrier zones; and (b) the energy levels of the sub-bands of the quantum well structures within the excitation and capture zones and the thickness of the tunnel barrier zone ar adjusted to provide a sufficient tunnelling probability for charge ca rrier tunnelling from the capture zone through the tunnel barrier zone into the excitation zone. USE - As a quantum well inter-sub-band photodetector (QWIP) useful for a focal plane array camera system or in uncooled monitor detectors for far IR lasers. ADVANTAGE - The modified single barrier well structure has improved response and increased detection sensitivity at low photo-currents, low noise, no dark current and low current levels, resulting in a large maximum integration time and to reduced cooling requirement.de608621667patent1997-19711505