Influence of tin oxide (SnO2) interlayer on the electrical and reverse current conduction mechanism of Au/n-InP Schottky junction and its microstructural properties

Abstract

The microstructural and current-voltage (I-V) characteristics of the prepared Au/SnO2/n-InP heterojunction (HJ) with an e-beam evaporated tin oxide (SnO2) film as an interlayer between the Au and InP substrate have been explored. The X-Ray diffraction and transmission electron microscopy results confirm the formation of the SnO2 thin film on InP surface. Then, the Au/SnO2/n-InP HJ diode is prepared and explored its electrical properties by the I-V approach. Low reverse leakage current is noted for HJ diode than the Au/n-InP Schottky junction (SJ). Higher barrier height (BH) is attained for the HJ compared to the SJ, which indicates that the insertion of SnO2 interlayer leads to an increase in the BH of SJ. Further, the BH is evaluated for the SJ and HJ diodes by Hernandez and Cheung's methods and matched with one another. Results exhibit that the interface state density (NSS) of HJ is less than the SJ, suggesting that the use of the SnO2 layer plays a key role in reducing NSS. Analysis of the reverse leakage current transport suggested the dominance of Poole-Frenkel emission in the lower bias region while the Schottky emission mechanism governs at upper bias region in both the SJ and HJ diodes. These results could provide expedient information of SnO2 interlayer for the design of metal/interlayer/semiconductor or heterojunction devices.