Excitonic versus Free-Carrier Contributions to the Nonlinearly Excited Photoluminescence in CsPbBr3 Perovskites

ACS Photonics ◽  
2021 ◽  
Author(s):  
Daria Khmelevskaia ◽  
Daria Markina ◽  
Pavel Tonkaev ◽  
Mikhail Masharin ◽  
Aleksey Peltek ◽  
...  
Keyword(s):  
Free Carrier

Effects of dopant concentration on the microstructure of tin- doped indium oxide thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 716-717
Author(s):  
I. A. Rauf
Keyword(s):  
Thin Films ◽  
Indium Oxide ◽  
Ionic Radius ◽  
Free Carrier ◽  
Electron Gun ◽  
Periodic Lattice ◽  
Oxide Thin Films ◽  
Transmission Electron ◽  
The Difference ◽  
Dopant Atoms

To understand the electronic conduction mechanism in Sn-doped indium oxide thin films, it is important to study the effect of dopant atoms on the neighbouring indium oxide lattice. Ideally Sn is a substitutional dopant at random indium sites. The difference in valence (Sn4+ replaces In3+) requires that an extra electron is donated to the lattice and thus contributes to the free carrier density. But since Sn is an adjacent member of the same row in the periodic table, the difference in the ionic radius (In3+: 0.218 nm; Sn4+: 0.205 nm) will introduce a strain in the indium oxide lattice. Free carrier electron waves will no longer see a perfect periodic lattice and will be scattered, resulting in the reduction of free carrier mobility, which will lower the electrical conductivity (an undesirable effect in most applications).One of the main objectives of the present investigation is to understand the effects of the strain (produced by difference in the ionic radius) on the microstructure of the indium oxide lattice when the doping level is increased to give high carrier densities. Sn-doped indium oxide thin films were prepared with four different concentrations: 9, 10, 11 and 12 mol. % of SnO2 in the starting material. All the samples were prepared at an oxygen partial pressure of 0.067 Pa and a substrate temperature of 250°C using an Edwards 306 coating unit with an electron gun attachment for heating the crucible. These deposition conditions have been found to give optimum electrical properties in Sn-doped indium oxide films. A JEOL 2000EX transmission electron microscope was used to investigate the specimen microstructure.

scholarly journals Superior photo-carrier diffusion dynamics in organic-inorganic hybrid perovskites revealed by spatiotemporal conductivity imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuejian Ma ◽  
Fei Zhang ◽  
Zhaodong Chu ◽  
Ji Hao ◽  
Xihan Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Relaxation Times ◽  
Charge Trapping ◽  
Free Carrier ◽  
Carrier Dynamics ◽  
Electron Hole ◽  
Inorganic Hybrid ◽  
Diffusion Dynamics ◽  
The Difference

AbstractThe outstanding performance of organic-inorganic metal trihalide solar cells benefits from the exceptional photo-physical properties of both electrons and holes in the material. Here, we directly probe the free-carrier dynamics in Cs-doped FAPbI3 thin films by spatiotemporal photoconductivity imaging. Using charge transport layers to selectively quench one type of carriers, we show that the two relaxation times on the order of 1 μs and 10 μs correspond to the lifetimes of electrons and holes in FACsPbI3, respectively. Strikingly, the diffusion mapping indicates that the difference in electron/hole lifetimes is largely compensated by their disparate mobility. Consequently, the long diffusion lengths (3~5 μm) of both carriers are comparable to each other, a feature closely related to the unique charge trapping and de-trapping processes in hybrid trihalide perovskites. Our results unveil the origin of superior diffusion dynamics in this material, crucially important for solar-cell applications.

4-QAM OFDM Data Switching via Free Carrier Absorption in Si-Rich SiC Waveguide

2021 ◽  
Vol 27 (3) ◽  
pp. 1-11
Author(s):  
Yen-Wei Hsueh ◽  
Chih-Hsien Cheng ◽  
Cai-Syuan Fu ◽  
Huai-Yung Wang ◽  
Bo-Ji Huang ◽  
...  
Keyword(s):  
Free Carrier ◽  
Free Carrier Absorption ◽  
Carrier Absorption ◽  
Data Switching

Free carrier absorption in heavily doped silicon layers

2004 ◽  
Vol 84 (13) ◽  
pp. 2265-2267 ◽  
Author(s):  
Joerg Isenberg ◽  
Wilhelm Warta
Keyword(s):  
Free Carrier ◽  
Free Carrier Absorption ◽  
Doped Silicon ◽  
Carrier Absorption ◽  
Heavily Doped
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