Fabrication and Characterization of Cu₂ZnSnS₄ Powders by a Hydrothermal Method

Abstract

In this study, Cu2ZnSnS4 (CZTS) powders are successfully synthesized by a simple hydrothermal method, and the concentration of thiourea, reaction time, reaction temperature, and precursor concentration ratio (Zn/Sn) are all examined in order to obtain the optimal conditions for this process. In addition, the characteristics of the resulting powder are examined using the X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Raman, transmission electron microscope (TEM) and ultraviolet–visible (UV–vis) techniques. The results indicate that the concentration of sulfur ions is 6 times of that of the copper ions, and that the production process required a reaction time of 72 h and a reaction temperature of 180 °C, and the energy gap of the CZTS powder is approximately 1.45 eV.

Effects of air-annealing on the electrical properties of p-type tin monoxide thin-film transistors

“…In all patterns, the obtained majority peaks are well matched with the (0 0 1), (1 0 1), (0 0 2), (1 1 2), (2 0 2) and (1 0 3) directions of SnO phase, but a notable reduction of peak intensity is observed in 290 • Cair-annealed tin oxide thin-films. In previous works, the reduction of XRD peak intensity corresponding to the SnO phase during the phase transformation from SnO to SnO 2 has been attributed to the degradation of crystallinity associated with an increase of SnO 2 [15,17]. The results in figure 5 are consistent with those in the previous works, and confirm the partial phase transformation of SnO to SnO 2 with a hightemperature air-annealing process.…”

“…Caraveo-Frescas et al investigated the effects of oxygen partial pressure and total pressure on the electrical performance of devices, and demonstrated high mobility p-type SnO TFTs (∼ 6.75 cm 2 (Vs) −1 ) [13]. Liang et al reported the effects of vacuum annealing temperature on the SnO thin-film and SnO TFTs [14], and Hsu et al examined the effects of electrode materials on the electrical performances of p-type SnO TFTs [15]. However, the effects of air-annealing were not fully investigated in SnO TFTs, although air-annealing has been known as the effective method which can improve the electrical performance of the oxide semiconductor-based TFTs [16].…”

Film Texture, Hole Transport and Field-Effect Mobility in Polycrystalline SnO Thin Films on Glass

“…On the other hand, the out-of-plane XRD patterns of the in-situ annealed films show stronger hkl diffractions along with strong 00l series compared with the direct-deposition films, suggesting SnO (101) plane is more preferentially grown by post-deposition annealing, which is consistent with previous reports. 6,22 When deposited on an amorphous substrate, a film surface prefers to expose the plane with the minimum surface free energy, 23 which is the (00l) plane for SnO and consistent with the above results. 24 In contrast for the post-deposition annealing, nucleation and crystal growth processes determine the film texture; i.e., inhomogeneous nucleation in general dominates at a low T a , while homogenous nucleation at higher T a .…”

“…500 • C) would be associated with the increase of Sn 4+ components resulting from disproportionation reaction of SnO. 22 It is worth noting that direct deposition at T s > 350 • C can effectively suppress the hole concentration to the order of 10 16 cm −3 and achieve higher mobility when compared with both the in-situ/ex-situ annealing cases. Calculated band structure of crystalline SnO reveals large differences in curvatures of the VBM bands between along the -M ([110]) and along -Z ([001]) or −X ([100]) directions, and suggests the strong anisotropy of hole transport.…”