Preparation And Photoelectric Properties Of Monolayer And Few Layer As₂S₃

In recent years, the graphene like two-dimensional materials have attracted a lot of attention, because of their excellent properties of the thin layer and single layer structure. One of the more important kind of material is sulfide with similar layered structure. Material is studied in the text of two-dimensional non-metallic sulfide As₂S₃, it has the characteristics of low dimension, broadband gap. So far, little research on monolayer and few layer As₂S₃. So this paper aims to mining the photoelectric properties of the material through the experiment and the test.In this paper, the "thick to thin, top to down" mechanical stripping method is used to prepare the single layer and a few layers graphene-like two-dimensional As₂S₃ material. Using the optical microscope for material layers of a preliminary determination, then Atomic force microscope tests were carried out on the target samples to determine the exact number of layers. In order to study the optical properties of single layer and thin layer As₂S₃, the materials were studied by Raman spectroscopy, photoluminescence spectra. Using micro device processing technology, we produced a field effect transistor （FET） used monolayer As₂S₃ as channel material and the transistor’s electrical properties were characterized. This paper has made the following main progress:1. The As₂S₃ samples of single layer and thin layer were successfully separated by physical mechanical stripping method. Through scanning electron microscope （SEM） and atomic force microscope （AFM） determination, accurate determination of the number of layers, and determine the thickness of the monolayer As₂S₃ is 0.7nm.2. According to the different layers of As₂S₃ materials, Raman spectroscopy was used to determine the change trend of Raman spectra from the bulk material to the thin layer, which Provides the oretical basis for the follow-up study.3. Based on the test and characterization of photoluminescence spectra of single layer and thin layer As₂S₃ materials, found the exciton emitting peak , and the exciton binding energy of As₂S₃ is calculated 250meV.4. Monolayer As₂S₃ field effect transistor was prepared, we found that As₂S₃ is a P type semiconductor through the test, Obtained by transfer characteristic curve the carrier mobility is 0.0154cm2/VS in back gate FET structure. Switching ratio is 102, and the threshold voltage is about -20V.,and analyze the reason.