Figure 1

(a) Electron micrograph of a line array having 25 lines in parallel (Sample $2_{1\mathrm{D}-2\mathrm{D}}A$). The width of the lines is 92 nm, the length is $10\mu \mathrm{m}$. (b), (c), and (d) Conductivity of the quasi 1D line array $1_{1\mathrm{D}}$ (b), the quasi 2D Hall-bar $1_{2\mathrm{D}}$ (c) and the quasi 3D Hall-bar $2_{3\mathrm{D}}$ (d) plotted versus temperature. The straight lines are guide for the eyes. The slope of the lines are given.Reuse & Permissions

Figure 2

(a) Conductivity change from 1 K to 22 mK of four line arrays (sample $1_{1\mathrm{D}-2\mathrm{D}}A,\dots ,4_{1\mathrm{D}-2\mathrm{D}}A$) plotted versus the wire width. The middle line is the best fit of the data to Eq. (4). The other two lines are fits using Eq. (4) and a diffusion constant of $12\times {10}^{-5}{\mathrm{m}}^2/\mathrm{s}$ and $6\times {10}^{-5}{\mathrm{m}}^2/\mathrm{s}$, respectively. In the inset, the conductivity change of four wire arrays (sample $1_{1\mathrm{D}-2\mathrm{D}}A,\dots ,4_{1\mathrm{D}-2\mathrm{D}}A$) is plotted versus $1/\sqrt{T}$. The slopes are guide for the eyes. (b) Conductivity change of the four line arrays (sample $1_{1\mathrm{D}-2\mathrm{D}}A,\dots ,4_{1\mathrm{D}-2\mathrm{D}}A$) plotted versus temperature. The lines are calculated using Eq. (4) and the parameters obtained by fitting the data in (a).Reuse & Permissions

Figure 3

Density of states at Fermi’s energy plotted versus carrier concentrations. The squares are calculated using the model of Masek et al. and the model of Tang and Flattè, respectively. The upper line describes a parabolic, fully spin polarized and nondegenerated band with high effective mass of $30m_e$ as an approximation for a detached impurity band. The grey line gives $N(E_F)$ calculated using a $6\times 6$ $k·p$ model with parameters for the GaAs valence band [27]. The circles are measured using EEI in 1D, 3D, and in the crossover regime from 1D to 2D.Reuse & Permissions