Effects of Na doping on CdS thin films and n-CdS/p-Si solar cells via chemical bath deposition method

Effects of Na doping on CdS thin films and n-CdS/p-Si solar cells via chemical bath deposition method

Un-doped and Na doped CdS thin films were deposited by chemical bath deposition method. The effects of Na doping onstructural, optical and electrical properties of CdS thin films and n-CdS/p-Si heterojunction were investigated. Crystalstructure of all CdS thin films was cubic with (111) preferred direction. High Na doping detoriated crystal structure andamorphous structure obtained for 3% Na doping. The grain size of thin films was decreased from 6.5 nm to 4.8 nm and surfacehomogeneity increased with Na doping. All samples had high band gap for CdS (2.42 eV) due to quantum size effect and bandgap of the samples was increased 3.65 eV to 3.84 eV as a function of Na content. Na doped CdS samples had higher resistivityand carrier concentration than that of un-doped CdS. Ideality factors of Na doped n-CdS/p-Si heterojunctions were greaterthan unity due to nanostructered CdS, which indicates that the diode exhibits a nonideal behavior. It was determined thatphotovoltaic behavior of n-CdS/p-Si prepared with high Na doped CdS dependent on different semiconductor structure (suchas depend on function of Na2SiO3 phase) occurred interface of CdS and Si.

Un-doped and Na doped CdS thin films were deposited by chemical bath deposition method. The effects of Na doping onstructural, optical and electrical properties of CdS thin films and n-CdS/p-Si heterojunction were investigated. Crystalstructure of all CdS thin films was cubic with (111) preferred direction. High Na doping detoriated crystal structure andamorphous structure obtained for 3% Na doping. The grain size of thin films was decreased from 6.5 nm to 4.8 nm and surfacehomogeneity increased with Na doping. All samples had high band gap for CdS (2.42 eV) due to quantum size effect and bandgap of the samples was increased 3.65 eV to 3.84 eV as a function of Na content. Na doped CdS samples had higher resistivityand carrier concentration than that of un-doped CdS. Ideality factors of Na doped n-CdS/p-Si heterojunctions were greaterthan unity due to nanostructered CdS, which indicates that the diode exhibits a nonideal behavior. It was determined thatphotovoltaic behavior of n-CdS/p-Si prepared with high Na doped CdS dependent on different semiconductor structure (suchas depend on function of Na2SiO3 phase) occurred interface of CdS and Si.