PHOTOLUMINESCENCE STUDIES OF QUANTUM-WELL STRUCTURES IN PULSED MAGNETIC-FIELDS

Magneto-photoluminescence spectroscopy at low temperatures has proved to be a powerful technique for investigating the electronic states of quantum well-type semiconductor heterostructures and offers a complime ntary tool to electrical transport studies. We have established a magn eto-optical facility at NHMFL-LANL and have undertaken a comprehensive investigation of magneto-excitonic and Landau transitions in a large variety of undoped and doped quantum-well structures. Fiber optic prob es are used to switch between steady state (to 18 T) and pulsed (to 65 T) magnetic fields applied perpendicular (Faraday geometry) and paral lel (Voigt geometry) to the growth axis of the 2D layers. The pulsed f ield mode requires that the spectroscopic data acquisition to be obtai ned in 1-2 ms in the 'flat-top' region at the peak of the field. A bro ad range of samples have been investigated in pulsed magnetic fields a s a function of temperature, sample geometry, and high pressure. Examp les include single and coupled double quantum wells, modulation-doped quantum wells, and single interface heterojunction structures. (C) 199 8 Elsevier Science B.V. All rights reserved.