Semi-insulating GaAs by controlled introduction of metallic nano-Schottkies

The formation of a semi-insulating GaAs-layer by overlapping depletion regions is investigated by controlled introduction of matrices of tungsten nano-Schottkies. By varying the spacing between the buried metal discs, the effect of the Schottky-depletion on the current transport is demonstrated. A change in the conductivity by 7 orders of magnitude is measured with a disc separation of 200 nm. In this semi-insulating material, the presence and height of a potential barrier between the discs is deduced from the temperature dependence of the current transport. Finally, the Schottky-barrier height of the buried metal discs is obtained from photo-conductivity measurements