APPLICATION OF MICROWAVE DETECTION OF THE SHUBNIKOV-DEHAAS EFFECT IN 2-DIMENSIONAL SYSTEMS

Microwave detection of the Shubnikov-de Haas (SdH) effect as a contact -free characterization technique for different types of two-dimensiona l semiconductor structures is explored in the low magnetic field regio n. The detection technique and the data analysis are described. The ch aracter and relevance of the single-particle relaxation time that can be detected by this technique are distinguished from the usual transpo rt scattering time. The measured values of the carrier concentration a nd single-particle relaxation time agree with electrical measurements, while the problem of making contacts on the structure is avoided. Unc ertainties in the analysis for the single-particle relaxation time are discussed. Cyclotron resonance, optically detected cyclotron resonanc e, and magneto-photoluminescence are applied as other contact-free tec hniques on the same samples. The results and suitability of these tech niques are compared with the microwave detection of the SdH effect.