Theoretical Investigation Of Phosphorene For Nanoelectronicapplications

Résumé: In this work we present a new broadband mid-Infrared (mid-IR) InGaZnO(IGZO) thin-film phototransistor (TF PT) based on both Black Phosphorus (BP) capping layer incorporating gold (Au) intermediate ultrathinfilm. The electronic and optical properties of bulk BP are carried outusing density functional theory (DFT) computations, including Perdew-BurkeErnzerhof Generalized Gradient Approximation (PBE-GGA) and the screenedhybrid (YS-PBE0) functionals with van der Waals correction. It is found thatBP exhibits interesting performances for mid-IR optoelectronic applications,at room temperature. To enhance the absorption of the BP material forbroadband mid-IR spectrum, a new strategy is proposed by optimizing thesensitive layer using finite-difference time-domain (FDTD) modelingand particle swarm optimization (PSO) approaches. The photoresponseproperties of the optimized broadband mid-IR IGZO TF PT with BP/Au/BPcapping layer are carefully analyzed. It is found that the proposed deviceshows high photodetection performances with a high current ratio exceeding180 dB over a wide voltage window. Besides, it is revealed that the introducedultrathin Au layer within BP enhances the absorbance capability over the midIR spectrum, which significantly improves the performance of the broadbandmid-IR sensor. Therefore, the proposed approach based on combining DFTanalysis with FDTD simulation supported by PSO optimization opens up anew strategy for the development of high-performance optoelectronic devices. In second part, a new high-performance broadband Infrared Optically Controlled Graphene Field-Effect Transistor (IR–OC–GFET) using strained black phosphorus sensing gate is proposed and investigated. The impact of the hydrostatic pressure on the optoelectronic properties of bulk Black Phosphorus (BP) is studied using density functional theory (DFT) calculations, including Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA) and the screened hybrid (YS-PBE0) function with van der Waals correction. It is revealed that the electronic and the optical properties of BP were substantially affected by the pressure effects, where the band gap energy decreases with increasing the hydrostatic pressure. The phototransistor drain current is calculated by self-consistently solving the Schrödinger/Poisson equations based on Non-Equilibrium Green's function (NEGF) approach. The impact of strained BP sensing gate material on the device sensing properties is investigated. It is found that the proposed device with strained sensing gate provides enhanced optical performances over the middle infrared (Mid-IR) spectral band, making it a new potential alternative photoreceiver for chip-level optical communications.

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