Depth profile composition studies of thin film CdS:Cu₂S solar cells using XPS and AES

Abstract

Surface composition and depth profile studies of chemiplated thin film CdS:Cu2S solar cells have been carried out using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) techniques. These studies indicate that the junction is fairly diffused in the as-prepared cell. However, heat treatment of the cell at 210 degrees C in air relatively sharpens the junction and improves the cell performance. Using the Cu(2p32/)/S(2p) ratio as well as the Cu(LVV)/(LMM) Auger intensity ratio, it can be inferred that the nominal valency of copper in the layers above the junction is Cu+ and it is essentially in the Cu2S form. Copper signals are observed from layers deep down in the cell. These seem to appear mostly from the grain boundary region. From the observed concentration of Cd, Cu and S in these deeper layers and the Cu(LVV)/(LMM) ratio it appears that the signals from copper essentially originate partly from copper in CuS and partly from Cu2+ trapped in the lattice. It is significant to note that the nominal valence state of copper changes rather abruptly from Cu+ to Cu2+ across the junction.

Self-organized CdS microstructures by anodization of Cd in chloride containing Na2S solution

“…4c). These peaks correspond very well to the literature for the compound CdS [35,36]. Also the XPS results indicate the presence of a small amount of oxide in the CdS film.…”

Structural studies on some doped CdS thin films deposited by thermal evaporation

“…For the CdS film, deposited on glass, the binding energy (BE) of the Cd 3d 5/2 peak, at 405.7 eV (Table 2), is close to the range of the previously reported values for CdS [13,14]. The S 2p photoelectron peak lies at 162.4 eV, also in the vicinity of the BE values characteristic of CdS [15,16].…”

Rationally Designed n–n Heterojunction with Highly Efficient Solar Hydrogen Evolution

“…[16] The peaks at 411.93 and 405.19 eV are attributed to the Cd 3d 5/2 and Cd 3d 3/2 of Cd 2 + in CdS. [17] The peak (Figure 3 e) at 162.16 eV is assigned to the S 2p of S 2À in CdS, [17] and the presence of other oxidation states at 168.96 eV may be due to the sulfate formed on surface. [18] The morphology and microstructure of CdS-ZnWO 4 heterojunctions are studied by SEM ( Figure S1 Figure 5 shows the UV/Vis absorption spectra of the obtained CdS-ZnWO 4 heterojunction with different CdS content.…”