Fabrication and application of multi-layer graphene pn homojunction diode with nitrogen doping

• Main Authors: Wan-Ting Yang, 楊婉婷
• Other Authors: Kuei-Yi Lee
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/92664k

碩士 === 國立臺灣科技大學 === 光電工程研究所 === 105 === Graphene is a two dimensional material with high surface area and high carrier mobility. Graphene is an attractive candidate for potential applications in optical and electrical devices due to these outstanding properties. Pristine graphene usually exhibits p-type behavior owing to the adsorption of oxygen and water vapor from the air. Therefore, modulating the grapheme electronic structure is an essential issue. Nitrogen doping is a facile approach used to tune the Fermi level above the Dirac point. Multi-layer graphene was synthesized in this study using chemical vapor deposition and then treated using nitrogen plasma. Under nitrogen plasma exposure the lateral graphene p-n junction was formed with the mask defining the doping regime. We investigated the device electrical characteristics using the half-wave rectifier. By modulating the nitrogen plasma power the current-voltage curve shows the Dirac point shifted from a positive value (+75 V) to a negative value (-55 V), indicating successful grapheme transformation into an n-type semiconductor. The nitrogen content increased from 1.4% to 2.8% with increased power. Pyrrolic-N content increased leading graphene FET to act as an n-type semiconductor. As shown from the Raman spectrum, the doping process induced defects. The graphene lateral homojunction exhibited diode properties. Good rectifier performance with very low distortion was identified by the oscilloscope. This device could be further applied in metal-oxide-semiconductor field-effect transistors and bipolar junction transistors.