FAR-INFRARED STUDY OF A LATERALLY CONFINED ELECTRON-GAS FORMED BY MOLECULAR-BEAM EPITAXIAL REGROWTH ON A PATTERNED (100)N(-GAAS SUBSTRATE())

A method of producing lateral confinement of an electron gas has been realized by using molecular beam epitaxy to grow a high mobility heter ostructure on a (100) n(+)-GaAs layer selectively etched to create a t wo-dimensional array of cavities through the n(+)-GaAs, which are boun d by higher index facets. Far-infrared cyclotron resonance (CR) spectr a unambiguously demonstrate that the electron gas formed inside the ca vities is confined in both lateral directions. Typical confinement ene rgies of 30 cm(-1) and widths of 2000 nm are derived from the spectra and magnetoresistance measurements. The effect of different n(+)-GaAs backgate biases is also investigated. Combining information from CR sp ectra with atomic force microscopy images provides a picture of the na ture of the lateral confinement in this structure. (C) 1997 American I nstitute of Physics.