Current transport and formation of energy structures in narrow Au/n-GaAs Schottky diodes

The current transport and formations of potential barrier height in narrow Au/n-GaAs Schottky diodes (SD) with a contact surface in length of 200 mu m, width of 1 and 4 mu m have been investigated. It was determined that features of current transport are in good agreements with the thermionic emission theory in the forward bias as like high-quality conventional (flat) SD. Features of current transport in the reverse bias also is well described by thermionic emission theory, but it has specific features unlike I-V characteristics flat SD. Forward bias of narrow SD current-voltage (I-U) characteristics are represented by straight lines in semi-logarithmic scale in a wide range, nearly nine order of current up to 0.7 V with near unit ideality factor. In the beginning of the reverse voltage, the current practically was extremely low, by increasing in voltage the current jump in steps approximately for 3-4 order in voltage of 3-4 V. then current increases linear for 3-5 order in semi-logarithmic scale by increasing in voltage up to nearly 7 V. Numerical values of parameters such as the saturation currents, the operating barrier height, ideality factor, dimensionless factor are obtained. The correlations between ideality factor and dimensionless factor were meaningful. The energy diagrams of narrow SD have been drawn in absence and presence of forward and reverse voltage. It is found that electronic processes in narrow SD are well described by energy model of real narrow metal-semiconductor contacts. The additional electric field arising in near contact area of the semiconductor because of creating contact potential difference between contact surface and to it adjoining free surfaces of the metal and semiconductor. (C) 2011 Elsevier Ltd. All rights reserved.