Excitonic photoluminescence characteristics of amorphous silicon nanoparticles embedded in silicon nitride film |
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Authors: | W Yu J Y Zhang W G Ding G S Fu |
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Institution: | (1) College of Physics Science and Technology, Hebei University, Baoding, 071002, P.R. China |
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Abstract: | We have investigated the photoluminescence (PL)
properties of amorphous silicon nanoparticles (a-Si NPs) embedded in silicon
nitride film (Si-in-SiNx) grown by helicon wave plasma-enhanced
chemical vapor deposition (HWP-CVD) technique. The PL spectrum of the film
exhibits a broad band constituted of two Gaussian components. From
photoluminescence excitation (PLE) measurements, it is elucidated that the
two PL bands are associated with the a-Si NPs and the silicon nitride matrix
surrounding a-Si NPs, respectively. The existence of Stokes shift between PL
and absorption edge indicates that radiative recombination of carriers
occurs in the states at the surface of the Si NPs, whereas their generation
takes place in the a-Si NPs cores and the silicon nitride matrix,
respectively. The visible PL of the film originates from the radiative
recombination of excitons trapped in the surface states. At decreasing
excitation energy (Eex), the PL peak energy was found
to be redshifted, accompanied by a narrowing of the bandwidth. These results
are explained by surface exciton recombination model taking into account
there existing a size distribution of a-Si NPs in the silicon nitride
matrix. |
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Keywords: | 78 67 -n Optical properties of low-dimensional mesoscopic and nanoscale materials and structures 71 20 Nr Semiconductor compounds 78 55 -m Photoluminescence properties and materials |
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