Characterisation of the photodetector and light emitting diode at above liquid nitrogen temperature

In this article, we have studied the behaviour of photodetectors and Light emitting diodes (LEDs) at above the liquid nitrogen (LN2) temperature. An o ptical cryostat has been used for this purpose. The data obtained from this investigation will be of help to decide the use of these devices for preci sion work at different cryogenic temperatures. A preliminary attempt has be en made to develop a theoretical basis for the experimental data, which is also important to understand the operation of these devices from room tempe rature to LN2 temperature. (C) 2000 Elsevier Science Ltd. All rights reserv ed.