Effect of double vacancy defect position on the Zigzag Phosphorene Nanoribbon Tunneling FETs

Document Type : Original Article

Authors

1 Department of Electrical Engineering, Faculty of Engineering, Ardakan University, P.O. Box 184, Ardakan, Iran.

2 Department of Electrical Engineering, Gorgan Branch, Islamic Azad University, Gorgan, Iran

Abstract

In this study, the effect of the position of a double-vacancy defect on the electrical performance of phosphorene nanoribbon tunneling field-effect transistors (TFETs) with a zigzag edge has been investigated. By varying the defect position along the length and width of the transistor channel, it was observed that the presence of defects in six studied positions—three along the length ("near source", "center", and "near drain") and three along the width ("center", "in between" and "near edge")—leads to a reduction in the transistor's on/off current ratio. The best performance is observed in the structure where the defect is located at the "in between" position of the channel width, with an on/off current ratio of 1600. Furthermore, the cut-off frequency decreases in all cases, with the smallest reduction occurring when the defect is positioned at the "in between" and "near edge" locations along the channel width, amounting to less than 10%. The calculations were performed using the Slater-Koster quasi-empirical method with DFTB-CP2K parameters. These findings demonstrate that the position of the double-vacancy defect has a significant impact on the electrical performance of phosphorene nanoribbon TFETs and should be considered an important factor in the design and fabrication of such transistors.

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