Barrier heights from ohmic to bandgap: Modified Al:GaAs Schottky diodes by MBE

The fabrication and properties of engineered Al:n-GaAs Schottky barriers are reported. It is demonstrated that these contacts can be designed to have any barrier height ranging from near zero (ohmic) to nearly bandgap. Molecular beam epitaxy (MBE) was used to grow the semiconductor and metal layers. Barrier height modification results from thin, highly doped semiconductor layers at the metal :semiconductor interface. An Al:n⁺-GaAs:n-GaAs structure gives reduced barriers. An Al:p⁺-GaAs: n-GaAs structure gives increased barriers. In the increased barrier devices, a 2kT current has been identified.