Technology advancement achieves high efficiency with low power. T-CNTFET with low power dissipation in high-speed applications is a suitable candidate for study. Due to the nanometer dimensions of CNTFETs, challenges such as the inability to achieve, reduced leakage current and sub-threshold swing, and increased transconductance and frequency cut are encountered. In addition, low ON current and ambipolar conduction are other drawbacks of conventional T-CNTFETs. Gaussian doping in the channel region of a newly developed design of tunneling carbon nanotube field effect transistor (T-CNTFET) is being evaluated for its performance. Doping is responsible for the short channel effect, increased ON current, and decreased cut-off frequency. There are three tiers of doping in effect. Doping is most concentrated at the drain and source ends of the channel and least concentrated in the central portion of the channel. Two-dimensional self-consistent Poisson and Schrodinger equations are used to model the apparatus. The differential method and the Green's function are used to resolve these equations. The simulation displays performance improvement in terms of transconductance, cutoff frequency, and sub-threshold swing when compared between existing and newly designed doped T-CNTFETs. Photo detectors are extensively used in many applications of communication systems.