Optimization of DMG-CNTFET Photo Detector for Different Illumination Conditions by Nano Scale Size and Doping Through Self-consistent Poisson- Schrodinger Equations

In this paper, we propose a nano scale Dual Material Gate Carbon Nanotube field-effect transistor (DMG-CNTFET) photo detector based on self-consistent 2D Poisson and Schrodinger equation. The main advantage of the proposed device is the improved performance due to dual material gate consisting of two laterally contacting Molybdenum and Titanium metals (M1,M2) with two different work functions (𝜙 𝑔𝑀1 , 𝜙 𝑔𝑀2 ). The 2D-Poisson equation is solved through finite difference method in open boundary for dark and illuminated condition. The Schrodinger equation is solved through non-equilibrium green function. The proposed DMG-CNTFET photo detector overcomes the problem of maximum thickness in gate oxide and gate size by nano-scaled sizing and highly doped source and drain. The gain and cut off frequency of the device are increased due to the reduced work function and the drain conductance. The characteristics of the proposed transistor are validated through various parameters such as drain current, transfer, sub threshold swing, trans-conductance, gain and cutoff frequency. From the simulation results, the proposed DMG-CNTFET photo detector provides better performance of trans conductance, gain and cutoff frequency. These device characteristics are the key parameters in the design and fabrication of various electronic circuitry and design and hence the relative performance improvement is achievable.