Inelastic Relaxation Processes in thin Superconducting NbN Films & in 2D Electron...

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9313920 Yngvesson A joint research project is undertaken between researchers at Moscow State Pedagogical University (MSPU), and University of Massachusetts at Amherst (UM/A). The two groups have during the last few years separately developed hot electron devices which have the potential for realizing a new generation of receivers and detectors for the range 0.5-3 THz (wavelengths 600 um to 100 um), with much lower noise temperature than any present receiver. MSPU has concentrated on thin film superconductors, while UM/A has utilized the two-dimensional electron gas (2DEG) medium at a semiconductor hetero-junction. The basic principles of the two devices are quite similar: a heated medium consisting of quasi-particles (in the superconductor case), or 2DEG electrons, is created, in which detection or mixing takes place. Recent work at both institution has resulted in available bandwidth with demonstrations GHz range. MSPU has shown that their devices mix up to at least 1.5 THz. A comparative study of inelastic relaxation processes in the two media is proposed, thus expanding the basic knowledge of inelastic relaxation processes a Howing development of optimum hot electron-based THz mixers. The two most promising materials known at the present time, NbN films and 2DEG at heterostructures of GaAs/A1GaAs, have been singled out for specific comparison. ***