Electro-optical characterisation for the control of silicon nanocrystals embedded in SiNx:H films
Résumé
In this work, electro-optical characterization techniques were used to control the size and density of silicon nanocrystals (nc-Si) in situ grown in non-stoichiometric amorphous hydrogenated silicon nitride (SiN x :H) films deposited by low-frequency plasma enhanced CVD (LF-PECVD). The average crystal size and density of the nc-Si were measured by HR-TEM. Photoluminescence (PL) and photocurrent (PC) spectra revealed emission and absorption phenomena related to confined excitons within nc-Si. By adjusting the deposition parameters, optimum PL and PC responses could be obtained, which are believed to correspond to the highest nc-Si density combined to an average crystal size equal to or slightly less than 4 nm. Such properties could then be used for the development of high efficiency solar cells. In this work, electro-optical characterization techniques were used to control the size and density of silicon nanocrystals (nc-Si) in situ grown in non-stoichiometric amorphous hydrogenated silicon nitride (SiN x :H) films deposited by low-frequency plasma enhanced CVD (LF-PECVD). The average crystal size and density of the nc-Si were measured by HR-TEM. Photoluminescence (PL) and photocurrent (PC) spectra revealed emission and absorption phenomena related to confined excitons within nc-Si. By adjusting the deposition parameters, optimum PL and PC responses could be obtained, which are believed to correspond to the highest nc-Si density combined to an average crystal size equal to or slightly less than 4 nm. Such properties could then be used for the development of high efficiency solar cells.