Structure, paramagnetic defects and light-emission of carbon-rich a-SiC:H films
نویسندگان
چکیده
The effect of vacuum annealing on local structure reconstruction, evolution of photoluminescence PL and paramagnetic defects in carbon-rich a-Si1−xCx :H films x=0.7 was studied. Strong enhancement of visible white-green PL was observed after annealing in the temperature range of 400–500 °C. Such enhancement was correlated with increasing of the concentration of carbon-hydrogen bonds in Si:CuHn accompanied with increase in the fluctuation of the interatomic potential. Complete disappearance of PL, “graphitization” of the carbon precipitates, and a strong increase in the concentration of the paramagnetic states were observed after annealing at 650 °C and above. The enhancement and the degradation of PL after different-temperature treatments are explained by the following competing effects: 1 enhancement of the radiative recombination due to passivation of paramagnetic defects with hydrogen and increase of localization of photoexcited electron-hole pairs due to formation of new Si:CuH and 2 enhancement of the nonradiative recombination through the paramagnetic states due to increase in their concentration caused by graphitization of carbon precipitates after hightemperature treatment. © 2008 American Institute of Physics. DOI: 10.1063/1.2946446
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