ABSTRACT
The noise spectroscopy of levels (among them even Landau levels in a two-dimensional electron gas) is a very sensitive method for their detection and investigation. Sometimes this method allows one to detect small concentrations of centers that are unlikely to be measured by most other methods. In addition, the particular physical properties of a capture cross section such as its temperature dependence and the influence of a centers charge state and of its chemical nature on the value of a capture cross section can be revealed by noise. By measuring the noise spectra one can determine the lifetimes t, and the advantage of this method is that it is stationary. Sometimes noise methods appear to be the only possible way to investigate centers. Finally, the dependences of on the type and concentration of different defects and on their parameters as well as on temperature, frequency and current presented above are useful for those who look for ways to reduce the noise in semiconductor resistors of different types.
