Propertise Of Cd-doped Sb₂S₃ Thin Films By Chemical Bath Deposited

Sb2S3 is an important direct band-gap compound semiconductor of the V-VI family. Due to the higher visible light absorption coefficient and the suitable band gap energy, Sb2S3 have wide range of applications such as thermoelectric cooler, various photovoltaic devices.Chemical bath deposition(CBD) is simple, enconomic and it has been used to deposit antimony sulphide film. However, the high electrical resistivity of chemical bath deposited Sb2S3 thin films limites its use in various optoelectronic devices. In this work, we reported the study on doping Sb2S3 thin films with Cd or Zn by CBD. The effects of Cd and Zn doping on the optical and electrical properties of Sb2S3 thin films were investigated. High resistive,near-intrinsic Sb2S3 thin film was used to forming a resistive switching memories FTO|Sb2S3|Ag. The RRAM properties of it was investigated on the first and the resistance switching mechanisms was analyzed.Cd- and Zn-doped Sb2S3 thin films were prepared by low-temperature bath deposition techniques, and the structure and the photoelectric properties were investigated. The introduced doping element did not change the crystalline structure of the original undoped film, and no impurity phases, while Zn doped appeared(200) preferred orientation. Zn doping narrowed the bandgap of Sb2S3(1.75 eV), but Cd doping widen the bandgap slightly from1.79 eV to 1.82 eV. Mott-schottky testing results showed that these Sb2S3 films with and without doped showed n-type conductivity.The heterojunctions of Ag/Sb2S3/CdS/FTO were prepared using these doped films, and the rectification behavior was measured. Cd-doped Sb2S3 thin films has better rectification characteristic than the non-doped and Zn-doped films.FTO| Sb2S3|Ag sandwich structure showed bipolar character, and the resistance switching mechanisms were analyzed. Increasing the film thickness can increase switch ratio, and switching stability was also improved. After 50 cycles scanning, I-V curve remined the basic shape, and the high and low resistance current keep on for 10000 s, which shows that FTO|Sb2S3(180nm)|Ag a good stablility. After annealing, these amorphous Sb2S3 thin films were transformed into crystallized films, memristive behaviors disappeared. The Sb2S3 memoristor with the activity electrode showed good switching property but with noble electrode gaveonly the Schottky contact characteristcs. Based on these conclusions, we deduced that resistive switching mechanism is consistent with the formation and rupture of conducting filaments.