Magnetotransport measurements on freely suspended two-dimensional   electron gases
  We present magnetotransport measurements on freely suspended two-dimensional electron gases from AlGaAs/GaAs heterostructures. The technique to realize such devices relies on a specially MBE grown GaAs/AlGaAs-heterostructure including a sacrificial layer. We fabricated simple Hall-bars as well as quantum cavities and quantum dot systems. We find well-pronounced Shubnikov-de Haas oscillations and observe commensurability resonances, allowing characterization of the electron gas in these 100 nm thin membranes. 
R.H. Blick, F.G. Monzon, W. Wegscheider, M. Bichler, F. Stern, and   M.L. Roukes