Noise sources of p-type CdTe single crystal

We have carried out noise measurements of CdTe single crystals, prepared by Institute of Physics, Charles University in Prague. These crystals are used as radiation detectors. Three types of significant noise were observed: low frequency noise, generation-recombination noise and thermal noise. The sample had very high value of 1/f noise, much higher than theoretical estimation. The depleted layers nearby the contacts are the dominating sources of noise. The contact whereof the hole concentration reduces with an applied electric field exerts prevailing effect on the noise. The resulting noise voltage is much higher than it must have been with the calculated quantity of charge carriers in the sample as a result of the depleted layers effect on the noise. Consequently the significant noise voltage appeared in the area nearby the contacts sums with the much lower value of the noise voltage in the homogenous area of the sample.