Ideal IR Detector

To be able to appraise various photodetector types, we will attempt here to define a general idealized infrared detector, which would, independently on a particular detection mechanism, satisfy aU the requirements posed for such a device. The performance of a real detector are then determined by the degree of compliance of its parameters, and thus defined perfect device. Of course, one can object that such an approach cannot be objective, since a particular application determines priorities in performance (for instance, for some military applications speed and detectivity are of primary importance, while costs are secondary for communication purposes one requires large speeds and low prices, etc.). In other words, one cannot define a unique set of characteristics that could describe all existing situations— an ideal detectors has as many definitions as there are applications [3]. 

The approach presented here should be understood in the following manner our ideal device actually sums most of the requirements that could be posed to an IR detector in any apphcation and surrounded by any environment. The purpose of 

Quantum effieieney n The number of photocairiers (electron-hole pairs) generated per a single photon of incident radiation, i.e., the probability of 1 incident photon generating a charge carrier pair also the ratio of the eurrent flux and the photon flux. In the systems where all photogentnated carriers eontribute to the signal current, equal to the ratio of abstnbed and incident powtn q X 

Photoelectric gain r The number of electrons flowing through the photodetector circuit per an absorbed photon the ratio of lifetime and transit time r = T/r  

Spectral range co The wavelength above which the photonic detector response quickly starts to drop, corresponds to the photons with an energy equal to the material bandgap, the unit is micrometer Ko = 1.239/ j Eg in [eV], A, in [pm] 

---

This work is dedicated to an analysis of the possible improvements of the performance of photonic detectors with a goal to use them at room temperature and to approach them as much as possible to the previously described idealized IR detector element. The presentation is limited to photoconductive and photovoltaic intrinsic detectors, although for the most part it can be generalized to any type of... 

---