Low dark current far infrared detector with an optical cavity architecture

Here we report designs For performance improvements of homojunction interfa cial workfunction internal photoemission (HIWIP) detectors for different fa r infrared regions. A design is given to reduce dark current to about 10 (e ) over bar /s for a 300 mum cut-off detector at 1.3 K, at a bias field of 5 00 V/cm by adjusting the thickness of the intrinsic layer to eliminate tunn eling component. The intrinsic region thickness and the bottom contact are used to obtain an optical cavity effect thus increasing the absorption to a lmost 100%. Increased responsivity due to the optical cavity effect is expe rimentally verified by using three detector structures, with three differen t cavity structures. (C) 2001 Elsevier Science Ltd. All rights reserved.