مطالعه حسگر گازي مبتني بر فسفرين با استفاده از اصول اوليه

A First-Principle Study of Phosphorene-based Gas Sensors

در اﯾﻦ ﭘﮋوﻫﺶ، ﺑﺎ اﺳﺘﻔﺎده از ﻣﺤﺎﺳﺒﺎت ﻣﺒﺘﻨﯽ ﺑﺮ ﻧﻈﺮﯾﻪ ﺗﺎﺑﻊ ﭼﮕﺎﻟﯽ، ﺟﺬب ﻣﻮﻟﮑﻮلﻫﺎي ﮔﺎز NH، CO3 ،H2S، و NO ﺑﺮ روي ﻓﺴﻔﺮﯾﻦ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﻣﯽﮔﯿﺮد. ﻣﮑﺎنﻫﺎي ﺑﻬﯿﻨﻪي ﺟﺬب ﻫﺮ ﯾﮏ از ﮔﺎزﻫﺎ و ﻣﮑﺎﻧﯿﺰم ﺣﺲ ﮔﺎزﻫﺎ ﺗﻮﺳﻂ ﻻﯾﻪي دو ﺑﻌﺪي ﺷﻨﺎﺳﺎﯾﯽ ﻣﯽ ﺷﻮد. ﻫﺮﭼﻪ اﻧﺘﻘﺎل ﺑﺎر ﺑﯿﺸﺘﺮي ﺑﯿﻦ ﻣﻮﻟﮑﻮل و ﻓﺴﻔﺮﯾﻦ اﺗﻔﺎق ﺑﯿﻔﺘﺪ، ﻣﻘﺎوﻣﺖ ﻻﯾﻪ ﻧﯿﺰ ﺗﻐﯿﯿﺮ ﺑﯿﺸﺘﺮي ﻣﯽ ﮐﻨﺪ و ﻟﺬا ﺑﺎ ﻣﺤﺎﺳﺒﻪي ﺗﻐﯿﯿﺮات ﻣﻘﺎوﻣﺖ ﻣﯽ ﺗﻮان ﮔﺎزﻫﺎ را ﺗﺸﺨﯿﺺ داد و ﻏﻠﻈﺖ آﻧﻬﺎ را ﺑﺪﺳﺖ آورد. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﻨﺪ ﮐﻪ ﻓﺴﻔﺮﯾﻦ ﺑﯿﺸﺘﺮﯾﻦ ﺣﺴﺎﺳﯿﺖ را ﺑﻪ ﮔﺎزﻫﺎي ﻣﺒﺘﻨﯽ ﺑﺮ اﺗﻢ N و ﺑﺨﺼﻮص ﻣﻮﻟﮑﻮل ﮔﺎز NO دارد. ﺑﻤﻨﻈﻮر ﺑﻬﺒﻮد ﻋﻤﻠﮑﺮد ﺣﺴﮕﺮ ﻓﺴﻔﺮﯾﻦ، ﺑﻪ ﻣﻄﺎﻟﻌﻪي ﻧﻘﺶ ﮐﺮﻧﺶ در ﻋﻤﻠﮑﺮد ﺣﺴﮕﺮي آن ﭘﺮداﺧﺘﻪ ﺷﺪ. ﻣﮑﺎنﻫﺎي ﺑﻬﯿﻨﻪي ﺟﺬب ﻫﺮ ﯾﮏ از ﮔﺎزﻫﺎ در ﮐﺮﻧﺶﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺪﺳﺖ آﻣﺪ و ﻣﮑﺎﻧﯿﺰم ﺗﻐﯿﯿﺮات اﻧﺮژي ﺟﺬب ﮔﺎزﻫﺎ در اﺛﺮ اﻋﻤﺎل ﮐﺮﻧﺶ ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪ. ﻧﺘﺎﯾﺞ ﺗﺎﺛﯿﺮ اﻋﻤﺎل ﮐﺮﻧﺶ ﻧﺸﺎن ﻣﯽدﻫﻨﺪ ﮐﻪ اﻋﻤﺎل ﮐﺮﻧﺶ ﺑﻪ ﺗﮏﻻﯾﻪ، ﻗﺎﺑﻠﯿﺖ ﺗﻔﮑﯿﮏ ﮔﺎزﻫﺎ را ﺑﻬﺒﻮد ﻣﯽ ﺑﺨﺸﺪ. در ﻧﻬﺎﯾﺖ ﻣﯽ ﺗﻮان ﮔﻔﺖ ﮐﻪ ﻋﻤﻠﮑﺮد ﺣﺴﮕﺮ ﮔﺎزي ﻓﺴﻔﺮﯾﻦ ﺑﺪون ﮐﺮﻧﺶ و ﻫﻤﭽﻨﯿﻦ ﺗﺤﺖ ﮐﺮﻧﺶ ﻗﺎﺑﻞ ﻗﺒﻮل اﺳﺖ و ﺗﻮاﻧﺎﯾﯽ ﺑﺎﻟﻘﻮهاي در ﺗﻔﮑﯿﮏ ﮔﺎزﻫﺎ دارد.

Two-dimensional materials have been the focus of research activities over the past decade. Their interesting and unique properties render them as excellent candidates for future electronic, optoelectronic, sensing, and bio applications. For gas sensing it is essential to maximize the ratio of the surface to volume of the sensor, which is the case for two-dimensional materials. This work presents a comprehensive study on adsorption properties of H2S, NH3, CO, and NO on phosphorene, by employing first-principle calculations. The optimized atomic sites, directions and the associated adsorption mechanisms are carefully analyzed. Transfer of charge between the gas molecule and the layer modifies the layer’s resistance. By evaluating the resistance variation, the concentration of gas molecules can be determined. The results indicate that nitrogen-based molecules especially NO, show the highest sensitivity among the studied gases. In addition, strain effects on sensor characteristics and adsorption behavior are investigated. The optimal locations for the absorption of the gases and the mechanism of absorption energy under various strain conditions are analyzed. The results indicate that sensitivity increases with strain and significantly improves the selectivity of the sensor. The results show that both strained and unstrained phosphorene are suitable candidates for sensitive gas sensing applications.