TRANSPORT-PROPERTIES OF SILICON DELTA-DOPED GAAS IN HIGH ELECTRON-DENSITY REGIME

We report results for Si layers embedded in GaAs, extending from the d elta-doped (delta-doped) range up to 6 monolayers derived by means of variable temperature resistivity and Hall effect measurements, seconda ry ion mass spectrometry and high resolution X-ray diffractometry tech niques. The conductivity transition from free carrier transport in ord ered delta-layers (< 1 ML) to strongly-localized two-dimensional varia ble range hopping transport under potential fluctuation disordered con ditions (> 4 ML) is clearly observed. This observation is in good agre ement with the secondary ion mass spectrometry and high resolution X-r ay diffractometry data. Results from the intermediate case with 2-3 ML s are also discussed.