Surface superlattices and quasi-one-dimensional conductors in GaAs HEMTs: how best to compare theory and experiment?

Summary form only given. The authors discuss evidence of (1) electron standing waves forming underneath a 2000-AA period Ti/Au Schottky grid or grating incorporated as a gate into a GaAs HEMT (high-electron-mobility transistor) structure, and (2) modulation of the scattering time due to intersubband scattering in an array of approximately 100 parallel wires of 400-AA width formed by laterally patterning a GaAs/GaAlAs heterostructure. The authors show how knowledge of the electron group velocity along with a scattering rate derived from Fermi´s golden rule can explain the observed effects. They compare the mobility modulation from intersubband scattering to the well-known prediction of Sakaki for increased mobility in quasi-one-dimensional wire due to the finite range of the scatterers. By first solving for the density of states and conductivity in a one-dimensional periodic potential, the authors show how to incorporate energy level broadening due to elastic and inelastic scattering, temperature broadening, and an increase in the dimensionality of the device by convolving with various known functions.