Investigation On The Influence Of Rapid Thermal Annealing On The Pulsed Laser Deposited SnS Thin Films And Devices

Currently, SnS is one of the most promising photovoltaic materials, and it is expected to become highly efficient solar energy conversion materials. Due to its stable chemical properties, abundancy, non-toxicity, the preparation of high quality SnS films is of great value in solar cell research. In this thesis, the influence of thermal annealing temperature on the properties of pulsed laser deposited SnS thin films, as well as the SnS thin film heterojunction device behaviors were systematically studied.The SnS thin films were grown by pulsed laser deposition on glass substrates at room temperature, and then the deposited films were rapidly annealed at 200,300,400,500 and 600 ℃ under flowing Argon atmosphere. The effects of rapid thermal annealing(RTA) temperature on the crystal structure, chemical composition, cross-section morphology, thin film thickness, surface morphology, optical properties and electrical properties of SnS thin films were studied by X-ray diffraction(XRD), laser Raman spectrometry(Raman), X-ray energy disperse spectroscopy(EDS), atomic force microscopy(AFM), field emission scanning electron microscopy (FESEM), ultraviolet-visible-near infrared spectrophotometer (UV-Vis-NIR) and Keithley 4200-SCS semiconductor parameter analyzer. The results show that the SnS thin films grow preferentially oriented in the (111) direction at different thermal annealing temperature, and the crystalline quality of the SnS thin films is the best at 400 ℃. The Raman characteristic peaks of SnS appear in the Raman spectra of the thin films. The atomic ratio is in close proximity to stoichiometry at 400 ℃. While increasing annealing temperature, the thickness of the films gradually decrease whereas the average particle sizes of the films increase. Its absorption coefficient in the visible region is in the order of 105cm-1. The direct bandgap of the film is 1.92eV at 400 ℃. While the thermal annealing temperature is 500℃, the film has a minimum resistivity of 14.97Ω3·cm.The p-SnS/n-Si heterojuction device was fabricated on Si substrate, and the p-SnS/n-ZnO heterojuction device was fabricated on glass substrate. Then the devices were characterized by a semiconductor parameter analyzer. The Ⅰ-Ⅴ measurement results show that the devices exhibit good rectifying behaviors with good photoresponse when illuminated by the White light.