Two step growth mechanism of Cu2ZnSnS4 thin films

Optical and structural investigation of Cu2ZnSnS4 based solar cells

“…In the literature, different methods for the sulphurization of metallic precursor layers have been investigated in order to increase the control of the stoichiometry along the thin film as well as the formation of secondary phases. Two of the most used methods are the sulphurization in a S flux or in a graphite box . While in the S flux method, the sample is exposed to an atmosphere with a constant S fraction, in the sulphurization in a graphite box the concentration of S changes along the process: increasing the temperature to values slightly higher than the one for the evaporation of S, the sample is exposed to an S‐rich atmosphere, and during the cooling of the sample, it is exposed to an S‐poor atmosphere.…”

Carrier Transport Properties

“…As mentioned earlier, the hole Hall mobility data of μ h~1 0-17 cm 2 /V s [20][21][22] were obtained on the CZTS films deposited on SLG substrates after sulfurization at 500-550 C for 15 min to 3 h. The diffusion of Na from the SLG substrates was found to have a profound effect on characteristics like grain size, crystal texture, and electrical conductivity of Cu(Ga,In)Se 2 [26,27] and CZTS films [28,29]. Thus, the relative high hole mobilities are thought to be due to the diffused Na impurities from the SLG substrates during sulfurization.…”

“…It is well known that carrier scattering at the grain or particle boundaries in polycrystalline or nanocrystalline samples usually greatly reduces carrier mobility. On the other hand, Thota et al [22] reported μ h~1 6.6 cm 2 /V s at p~9.1 × 10 17 cm −3 with resistivity of~6.8 × 10 3 Ω/sq. Liu et al [19] obtained μ h~3 0 cm 2 /V s at p~3.9 × 10 16 cm −3 with resistivity of~5.4 Ω cm from CZTS film deposited by reactive magnetron cosputtering (H 2 S/Cu/Zn/Sn) on an SLG substrate.…”

“…They obtained two different nanocrystalline films, kesterite-and WZ-type CZTS films, on the glass substrates by a drop-coat technique using a dense tetrachloroethylene solution of CZTS nanocrystals. The hole Hall mobilities of~10-17 cm 2 /V s were obtained on CZTS films prepared by sulfurization of sputtered metallic precursors on SLG substrates [20][21][22]. The Hall-effect measurements gave the results μ h~5 6 cm 2 /V s at p~1.3 × 10 15 cm −3 with resistivity of~1.2 × 10 4 Ω cm for the kesterite-type CZTS nanocrystalline film and μ h~4 .3 cm 2 /V s at p~1.5 × 10 17 cm −3 with resistivity of~8.8 × 10 3 Ω cm for the WZ-type CZTS nanocrystalline film.…”