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Synthesis And Electrical Performance Characterization Of Quasi-one-dimensional K-Cu-S Ternary System

Posted on:2016-04-26Degree:MasterType:Thesis
Country:ChinaCandidate:W J WangFull Text:PDF
GTID:2271330473454996Subject:Integrated circuit engineering
Abstract/Summary:PDF Full Text Request
Due to the excellent photoelectric properties, metal sulfide nanomaterials have become the frontier hot spots in fields such as solar energy conversion, optoelectronic devices and catalyze. The successful doping for Cu-S system, not only effectively change the Cu-S system crystal structure and optical properties, but also help to expand sulfide nanomaterials in new applications in the study of nanometer optoelectronics. K-Cu-S ternary system is a kind of important thiocuprates, according to the different contents of K+ doped in the Cu-S lattice system, different coordination numbers of copper ions and different positions of copper atoms, there forms different structures of the ternary sulfides with different properties. Such as the KCu7S4 with quasi one-dimensional structure showed abnormality in the low temperature phase change and resistance, and it can be applied as super capacitor. This paper we discuss the K-Cu-S ternary system of quasi one-dimensional nanostructures synthesize through liquid phase controlled synthesis method, what is more, we systematically characterize its electricity, photoelectric properties. The specific research work are as follows:1. Monoclinic KCu3S2 microbelts were successful synthesized through composite-hydroxide mediated (CHM) approach (a mixture of NaOH and KOH with Na /K atomic ratio of 48.5:51.5), using Na2S · 9H2O as sulfur source and CuCl as copper source. SEM images show the product with lengths about 30~60 μm, widths of 500 nm1 μm and thicknesses of 200~500 nm. The bandgap of KCu3S2 microbelts is calculated to be~1.62 eV by ultraviolet-visible absorption spectrum, photoluminescence and X-ray photoelectron spectrum. Electrical characterization shows that the conductivity of the KCu3S2 microbelts is about 1.85x 103 S cm-1. The bottom-gate field-effect transistor (FET) based on a single KCu3S2 microbelts revealed the n-type conduction of the KCu3S2 microbelts.2. A KCu3S2/Au Schottky diode was fabricated on the SiO2 substrates. I-V tests show that the rectification ratio of KCu3S2 microbelt/Au schottky diode is between 102103, which it has good rectifying characteristics. The schottky junction has strong sensitivity under the white light illumination from the optical microscopy with the power of 3.5 mW cm-2, which shows a photoresponse ratio Ilight/Idark~50 and a rapid response time less than 0.5 s. with those good performances above, KCu3S2 microbelts is expected to be used as a high-performance white light detector.3. Monoclinic KCu7S4 microbelts were successful synthesized through composite-hydroxide mediated (CHM) approach (a mixture of NaOH and KOH with Na /K atomic ratio of 48.5:51.5), using Na2S · 9H2O as sulfur source and CuCl2 as copper source. SEM images show the product with lengths about 30~60 μm, widths of 100 nm ~0.3 μm and thicknesses of 50~80 μm. Electrical characterization shows that the conductivity of the KCu3S2 microbelts is about 6.85x 102 S cm-1. The bottom-gate field-effect transistor (FET) based on a single KCu3S2 microbelts revealed the p-type conduction of the KCu3S2 microbelts.
Keywords/Search Tags:KCu3S2 microbelts, KCu7S4 microbelts, schottky junction, photodetector
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