Effects of Cu2−xS phase removal on surface potential of Cu2ZnSnS4 thin-films grown by electroplating

Enhancement of photo‐conversion efficiency in Cu2ZnSn(S,Se)4 thin‐film solar cells by control of ZnS precursor‐layer thickness

“…If the samples are exposed to the air, then the samples can be oxidized. However, previous studies have reported that chemical etching with potassium cyanide (KCN) or hydrochloric (HCl) can produce a surface that is not oxidized . When the samples were dimpled, we used alumina nanoparticles to polish them and then etched them with DI water for 10 min to clean the film surface.…”

Nanoscale photovoltage mapping in CZTSe/CuxSe heterostructure by using kelvin probe force microscopy

“…X-ray diffraction (XRD) patterns (figure 2(a)) and Raman spectra (figure 2(b)) of the CZTSe and Cu 2−x Se thin film samples can be completely indexed as the pure phases (JCPDS no. 52-0868 and 34-171 were used as reference for the XRD peaks) [18,19]. The UV-visible spectroscopic measurements show band gaps of 1.12 eV (CZTSe) and 1.72 eV (Cu x Se) as specified in supplementary information is available online at stacks.iop.org/ MRX/7/016418/mmedia.…”

“…Cu x Se is found usually in CZTSe thin films due to Sn-loss during selenization which influences the Cu content, resulting in the formation of secondary phases. The impurity phase present on the top surface can be etched by a chemical process, but its presence across the cross-section can be a critical cause of a shunt path across the absorber of the CZTSe solar cell [18]. Improvement in the photovoltage directly depends on controlling the recombination in the GB of CZTSe and at the interfaces between CZTSe/secondary phases [27].…”

“…Secondary phases (e.g. Cu x Se, ZnSe) may also be present in the form of nanoscale features between CZTSe grains [18,19]. The highest efficiency (>20%) for Cu(InGa)Se 2 (CIGS) is attributed to the grain boundary structure of CIGS having a Cu-poor structure, which acts as a potential barrier for holes and attracts minority carrier electrons, thus making carrier separation faster [1,20].…”

Carrier transport and surface potential over phase variations in the surface and bulk of highly efficient Cu2ZnSn(S,Se)4 solar cells

“…Excluding quaternary phases, unexpected secondary phases and accompanying defects have been known to hinder electron-hole (e-h) separation, which affects the open-circuit voltage (V OC ) and short-circuit current density (J SC ). [9][10][11][12][13][14] The secondary phases mainly observed in kesterite materials are Cu x (S,Se), 15,16 Cu 2 Sn(S,Se) 3 , 10 Sn(S,Se) x , 17 and Zn(S,Se). 18 Cu-and Sn-related secondary phases typically have smaller energy band gaps (E g ) than CZTSSe quaternary phases.…”