Transport measurements and analytical modeling of extraordinary electrical conductance in Ti-GaAs metal-semiconductor hybrid structures

We present a comprehensive study of a phenomenon, extraordinary electroconductance (EEC), in microscopic metal-semiconductor hybrid (MSH) structures at room temperature. Our artificially designed MSH structure shows highly efficient external electric field sensing properties not exhibited by bare semiconductor structures. The microscopic device is fabricated from a GaAs epitaxial layer with a Ti/Au shunt subject to an external electric field and gives a maximum 5.2% EEC effect corresponding to an external electric field resolution of 3.05 V/cm at a bias field of 2.5 kV/cm. Moreover, the study reveals a strong dependence of the transport properties on the geometry of the MSH. An analytical two-layer model is developed which provides good agreement with the experimentally observed data. We propose that scaled down nanoscopic EEC sensor arrays can be used as an imaging technique for the charge distribution on a single cell surface in real time.