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The Current-Voltage (I-V) characteristics are highly affected during the gas adsorption by the ZnO nano structure. Metalloid Porphyrin has been proven as an attractive bio-sensor for its high sensitivity towards the adsorption of CO, NO and O2 gas molecules. Among these sensors CNT is one of the popular bio-sensor. CO gas can efficiently sense by Porphyrin bio-molecule using single wall CNT (SWCNT) as electrodes. The gas sensing ability for graphene has been increased by introducing dopants. First principle investigation has been made possible for arm chair Boron nitride nano ribbons to sense PH3 gas molecules. Detection of conformational changes in protein can be diagnosis using multi layer graphene electrodes. Arm chair graphene nano ribbon is useful to sense the bio-molecule Anthracene in molecular level of foreign particle detection. Carbon Nano Tubes (CNTs) are sensitive towards the adsorption of foreign molecules like NO2 gas. Boron nitride zigzag nano wire sensor has been designed to sense the presence of chlorine gas molecules. The various nano sensors have already been designed using Density Functional Theory (DFT) and Non Equilibrium Green’s Function (NEGF). GaAs is one of the highly appreciable and attractive direct band gap semiconductors. GaAs is a direct band gap semi-conductor which has been used as nanopore electrodes for this two probe theoretical study. In the world of nano-bio technology, the researchers are continuously trying to build a two-way bridge between the bio-technology and semiconductor nanotechnology. Nucleotides are the basic backbone of single strand DNA (ss-DNA). When these molecules are attached with glucose and phosphate groups then they converts themselves as nucleotides. These bio-molecules are the basic building blocks of DNA. The heterogeneous bio-molecular chain is made with Adenine and Thymine bio-molecules. The attractive potential of conductivity modulation suggests this heterogeneous bio-molecular chain as an application in future generation bio-sensor technology. In this paper we attempt to present the molecular model sensor with circuit elements. The quantum ballistic transmission through the direct band gap semi-conductor material GaAs nanopore increases during the Ammonia and Phosphine gas adsorption by the heterogeneous chain. Adsorption of single molecule Ammonia and Phosphine increases the conductivity of the heterogeneous bio-molecular chain at room temperature. This Current-Voltage sensitivity has been raised upto 40 and 9.3 times with the presence of single Ammonia and Phosphine molecules respectively under the ultra low bias voltage application. It has been found that Current-Voltage characteristics of the bio-molecular chain highly depend during the foreign gas molecules adsorption. The hetero-junction chain has been passed through the multi layer GaAs nanopore electrodes.
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This modeling and simulation technique plays an important and crucial role in the fast growing semiconductor based nanotechnology field. This paper presents Density Functional Theory and Non-Equilibrium Green’s Function based First Principles calculations to explore the sensing property of Adenine and Thymine based hetero-junction chins for Ammonia and Phosphine gas molecules.