Noise gain vs. capture probability in single quantum well infrared photodetectors at low bias voltages

摘要

A model of low frequency current noise S-l(O) is developed for single quantum well (QW) infrared photodetectors. A retarding mechanism, between subsequent electron injections in the QW structure, might dominate under a given threshold voltage value corresponding to the inversion of the electric field at the collector barrier. By considering this effect in terms of correlation between subsequent stochastic elementary events, the expressions of S-l(0) and of noise gain g(n), defined as S-l(0)/4eI, are deduced. In particular, it is found that, when the applied voltage V --> 0 and the capture probability p(c) --> 1, the noise gain g(n) reaches the minimum value g(n) = 1/4. O 2001 Elsevier Science B.V. All rights reserved. [References: 17]