Effect of ZnO seed layer on the electrical characteristics of Pd/ZnO thin-film-based schottky contacts grown on n-si substrates

Abstract

The electrical characteristics of Pd/ZnO thin-film Schottky contacts grown on n-Si substrates with and without using a ZnO seed layer by simple thermal evaporation method have been investigated. The structural, morphological, and optical properties of the ZnO thin films were investigated using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and photoluminescence (PL) measurements. The Schottky devices with ZnO seed layer exhibits superior diode characteristics (with excellent rectification ratio of ∼2.5 ×103, \hbox{ barrier height} = 0.81 eV, and \hbox{ ideality factor} = 1.46 at room temperature to those without using ZnO seed layer. This is attributed to the reduction of native defects states from the ZnO thin film surface caused by ZnO seed layer as evidenced by the room-temperature PL measurement. Thus, the use of ZnO seed layer on the n-Si substrates may be treated as an effective approach for fabricating Pd/ZnO thin-film-based Schottky diodes on n-Si substrates for electronic and optoelectronic applications. © 2002-2012 IEEE.