Selective detection of secondary phases in Cu<inf>2</inf>ZnSn(S, Se)<inf>4</inf> based absorbers by pre-resonant Raman spectroscopy

Improving efficiency of electrostatic spray-assisted vapor deposited Cu2ZnSn(S,Se)4 solar cells by modification of Mo/absorber interface

“…4 shows the Raman spectra of the back contact of the absorber obtained from samples A and B after the removal of the absorber, respectively. The spectrum from sample A was characterized by the presence of a dominant peak at 252 cm −1 which agrees with the main peak reported for ZnSe [22]; the main peak at 190 cm −1 and weaker contributions at 169 cm −1 and 221 cm −1 has been identified with the vibrational mode of binary SnS [23][24]. It is important to note that due to the Zn-rich conditions used in these films (as confirmed by EDX in Table 2), the probability to form Zn-based binary phases is likely.…”

XPS analysis and characterization of thin films Cu2ZnSnS4 grown using a novel solution based route

“…5 are present at 486.4 and 494.5 eV, which confirms that Sn is in the þ4 oxidation state [18,19]. The Cu 2p core level spectrum exhibits binding energies for the Cu 2p 3/2 and Cu 2p 1/2 peaks at 932.8 and 952.3 eV, respectively, and a peak splitting of 19.5 eV, enabling the conclusion that copper is in the þ 1 oxidation state and indicating the formation of Cu(I) [16,18]. Peaks Zn 2p 3/2 Fig.…”

“…The CTS film deposited by both methods exhibit Raman peaks at 313 and 350 cm À 1 and the evaporated CTS sample shows an additional peak at 290 cm À 1 ; these three peaks have been assigned by other authors to the A 0 symmetry vibrational modes from the monoclinic Cu 2 SnS 3 phase [14][15][16], indicating that the new developed method allows to synthesize thin films of CTS that grow only in the Cu 2 SnS 3 phase.…”

Formation and impact of secondary phases in Cu-poor Zn-rich Cu2ZnSn(S1−Se )4 (0≤y≤1) based solar cells

“…The key is to employ excitation lights with photon energy close to the band gap of secondary phases to get resonant excitation conditions. It was found that UV light (325 nm) is effective to identify ZnS, while blue light (458 nm) is sensitive to inspect ZnSe [23,24]. Another relevant issue is that, Zn(S,Se) usually presents at the Mo/Cu 2 ZnSn(S,Se) 4 interface, which can be difficult to detect by Raman measurements performed on the surface, taking into account that the penetration depth of the Raman excitation light is only about 100 nm.…”