Temperature Dependent Current Transport Mechanism of Photopolymer Based Al/NOA60/p-Si MPS Device

A photopolymer based Al/Norland Optical Adhesive 60 (NOA60)/p-Si MPS (metal-polymer-semiconductor) device was fabricated by a combination of vacuum evaporation and smear technique. The current transport properties of the device were investigated by using the forward bias current-voltage (I-V) characteristic in the temperature range of 80-300 K. The cross-sectional structure of polymer/semiconductor was revealed by the scanning electron microscope (SEM) image and it was seen that the NOA60 photopolymer was tidily coated on the p-Si surface. According to the I-V measurements at room temperature, the MPS device exhibits a good rectification ratio of 8140 at +/- 1 V. The temperature-dependent I-V measurements (I-V-T) were analyzed based on the thermionic emission (TE) theory and an abnormal increase in zero-bias barrier height (BH) and a decrease in ideality factor (n) was observed with increasing temperature. Additionally, two different linear regions with distinct values from the theoretical value of the Richardson constant (A*) were observed in the conventional Richardson plot. Such deviations from the ideal TE theory have been attributed to the effect of BH inhomogeneities. Gaussian distribution (GD) of the BH model has applied the I-V-T results and the double GD BH with mean values of 0.75 +/- 0.08 eV (80-140 K) and 1.02 +/- 0.11 eV (140-300 K) were calculated. Moreover, the A* value of 31.4 A/cm(2)K(2) was calculated close to the known value of p-Si from the modified Richardson plot. Thus, it has been concluded that the current transport of the Al/NOA60/p-Si MPS device can be explained by TE with a double GD BH model for a wide temperature region.

Automated summary

A device based on Al/Norland Optical Adhesive 60 (NOA60)/p-Si MPS was fabricated using photopolymer. The current transport properties of the device were investigated and a good rectification ratio was observed at room temperature. The temperature-dependent study revealed an increase in barrier height and a decrease in ideality factor with increasing temperature. The Gaussian distribution model and Richardson plot were employed to calculate the barrier height.