Preparation of mixed copper/PVA nanocomposites as an interface layer for fabrication of Al/Cu-PVA/p-Si Schottky structures

In this study, simple ultrasound-assisted method was used for prepare the composite of (Cu-doped PVA) interfacial layer between metal and semiconductor (Al/p-Si). The scanning electron microscopy (SEM) images of the prepared (Cu-doped PVA) nanocomposites have shown an uniform fish scale shape, which are about 100 nm long and several tens of nm in width. Both the Al/p-Si (MS) and Al/(Cu-PVA)/p-Si (MPS) structures were fabricated on the same Si wafer to investigate the effect of this polymer layer on the electrical characteristics by using the current-voltage (I-V) and capacitance/conductance-voltage (C/G-V) measurements at room temperature. The values of reverse-saturation current (I-o), ideality factor (n) and zero-bias barrier height (Phi(Bo)) were obtained from the liner part of the forward bias I-V plot as 6.6 x 10(-10) A, 3.67 and 0.84 eV for MS structure and 1.82 x 10(-8) A, 4.18 and 0.76 eV for MPS structure, respectively. MPS structure has a good rectifier behavior with low leakage current in comparison to the MS structure. The high values of n was attributed to the barrier inhomogeneity at Al/p-Si, special density distribution of N(ss )at (Cu-PVA)/p-Si interface and both the existence of native SiO2 and deposited of (Cu-doped PVA) interlayer at M/S interface. The energy dependent values of N-ss were obtained from the forward bias I-V data and they ranged from the 1.85 x 10(13) eV(-1) cm(-2) (0.60 eV - Ev) to 7.40 x 10(13) eV(-1) cm(-2) (0.40 eV - Ev) for MS structure and 9.81 x 10(12) eV(-1) cm(-2) (0.67 eV - Ev) to 5.26 x 10(13) eV(-1) cm(-2) (0.47 eV - Ev) for the MPS structure. Experimental results show that the (Cu-PVA) interlayer can be successfully used instead of traditional insulator layer because of the saturation of dangling bonds.