فرآيند ﺗﮑﺜﯿﺮ ﭼﻨﺪ اﮐﺴﯿﺘﻮن در ﻧﺎﻧﻮﺳﺎﺧﺘﺎرﻫﺎي ﻣﺮﮐﺐ ﺳﯿﻠﯿﮑﺎن - ژرﻣﺎﻧﯿﻮم

در ﻓﺮآﯾﻨﺪ ﺗﮑﺜﯿﺮ ﭼﻨﺪ اﮐﺴﯿﺘﻮن، ﺟﺬب ﯾﮏ ﻓﻮﺗﻮن در ﺷﺮاﯾﻂ ﻣﻌﯿﻦ ﻣﯽﺗﻮاﻧﺪ ﺑﻪ ﺗﻮﻟﯿﺪ ﺑﯿﺶ از ﯾﮏ اﮐﺴﯿﺘﻮن ﻣﻨﺠﺮ ﺷﻮد و در ﻧﺘﯿﺠﻪ ﺑﺎزده اﻓﺰاره ي ﺟﺎذب ﻧﻮر را اﻓﺰاﯾﺶ دﻫﺪ. در اﯾﻦ ﻧﻮﺷﺘﺎر ﺑﺎ اﺳﺘﻔﺎده از روﺷﯽ ﺑﺲ ذره اي، ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺷﺒﯿﻪﺳﺎزي ﻓﺮآﯾﻨﺪ ﺗﮑﺜﯿﺮ ﭼﻨﺪ اﮐﺴﯿﺘﻮن در ﻧﺎﻧﻮﺳﺎﺧﺘﺎرﻫﺎي ﻣﺮﮐﺐ ﺳﯿﻠﯿﮑﺎن - ژرﻣﺎﻧﯿﻮم اراﺋﻪ ﻣﯽﺷﻮد. ﻧﺘﺎﯾﺞ ﺷﺒﯿﻪﺳﺎزيﻫﺎ ﻧﺸﺎن ﻣﯽدﻫﻨﺪ اﻓﺰاﯾﺶ ﺗﻌﺪاد اﺗﻢﻫﺎي ﺳﯿﻠﯿﮑﺎن در ﻧﺎﻧﻮﺳﺎﺧﺘﺎر ﺑﺎﻋﺚ اﻓﺰاﯾﺶ آﺳﺘﺎﻧﻪي ﺗﮑﺜﯿﺮِ ﺑﯿﺶ از ﯾﮏ اﮐﺴﯿﺘﻮن و ﻧﯿﺰ اﻓﺰاﯾﺶ ﺑﯿﺸﻨﻪي ﺟﺬب ﻧﻮري ﻣﯽﺷﻮد.

In the multiple exciton generation (MEG) process, absorption of a photon in a given condition can lead to the generation of more than one exciton, increasing the efficiency of the light harvesting devices. In the present study, we have investigated the generation of multiple exciton in SiGe nanostructures by using a many-body approach. In this way, by particle swarm optimization method and a special algorithm, we obtained the most stable geometry of SiGe nanostructures. Then, we define the MEG quantum probability parameter and obtain the optical absorption spectrum. In general, the comparison of the MEG process in various nanostructures can be done by comparing the magnitudes of three parameters knowns as the MEG quantum probability, the MEG threshold, and the intensity of the light absorption in the range of energy of the incoming photon. The simulation results show that the larger the number of silicon atoms in the nanostructure, the larger the MEG threshold and the stronger the optical absorption. Furthermore, the numerical results also show that the smaller the number of Ge atoms in the SiGe nanostructure, the larger is the peak intensity of the absorption spectrum.