Multifunctional Semiconductor Core Multimaterial Glass Fibers

Multiple materials and/or novel structures are incorporated into a single fiber,which is called multimaterial fibers,aim to realizing different optical,electronic,thermomechanical,and acoustic properties.However,most of research only focuses on single function,which undoubtedly limits the applications of multimaterial fibers.In this paper,semiconductors with multiple properties?GeSe?Cu-Ag?Ag-Se?and material with novel fast phase transition property?Sb?were selected as the fiber core precursor materials.Based on the technical accumulation of our research group in preparation of multimtaerial fibers,we hope to yield a variety of high performances in a single multimaterial glass fiber.Detailed research contents and results are as follows:?1?Continuous GeSe core borosilicate glass-clad multimaterial fibers were prepared by molten core method.The diameter of fibers and fiber cores was 300-700?m and 30-70?m,respectively.XRD and Raman spectroscopy indicate that the as-drawn fiber core is an orthorhombic GeSe crystal phase.The EPMA and XPS measurements indicate that there exists a little amorphous GeO₂ in the core,which is formed by the combination of the diffused O and Ge during the fiber drawing process.The photocurrent test shows that the number of carriers of the crystalline GeSe semiconductor in the fiber core increases with the excitation of a large number of external photons,and the current increases remarkably when the GeSe core fiber is irradiated by an external laser.It is calculated that the conductivity of the GeSe core fiber is increased to 204%when compared with that in dark condition under the illumination of 808 nm laser.The Seebeck coefficient of the GeSe core fiber at 300 K is566.03?V/K,which is equivalent to the that of the GeSe bulks.Its conductivity is 55.56 S/m,which is 3-4 orders of magnitude higher than the that of the pure GeSe bulks reported in the literature.The power factor PF of the GeSe core fiber is 0.18?W?K^-2?cm^-1,which is much larger than the value of the pure GeSe bulks.The results of the pressure sensing test show that the conductivity of the GeSe core composite fiber changes by 10.45%under the condition of0.5 N.All the results indicate that GeSe core borosilicate glass-clad multimaterial fibers have potential in multiple fields like photo-detecting,thermoelectric conversion and pressure sensing.?2?Cu-Se or Ag-Se compound semiconductor core multimaterial optical fibers with glass-clad have been fabricated.The crystal phase of the core of the Cu-Se core fiber is a mixed phase of CuSe and Cu₃Se₂.Both CuSe powder and Cu-Se fiber core have relative strong absorption in the range of 200-2500 nm and the strongest absorption region is500-1000 nm.The conductivities of Cu-Se core fiber under 532 nm and 808 nm laser illuminations are decreased to 60.5%and 80.4%respectively,when compared with that in dark condition,indicating that Cu-Se core fiber could be applied in photoelectric detection and optical switch.During the drawing of Ag-Se core fiber,Ag powder reacts with Se powder to form Ag₂Se.When the temperature is around 1100^°C,the temperature inside the preform may not be sufficient to completely melt Ag₂Se,whose melting point is 880^°C.As a result,the Ag₂Se core fibers are not available.?3?The Sb core fiber with excellent continuity was successfully prepared by the molten core method.The EPMA test shows that the main element is Sb in the fiber core and Si and O in the clad.There exists distributed uniformly O in the fiber core.However,the O element doesn't bind Sb to form Sb₂O₃ crystal according to XRD and Raman spectroscopy.At room temperature?25^°C?,the current-voltage curve of the Sb core is linear.When the temperature rises,its conductivity increases but keep unchanged when the temperature increases furtherly.The Sb core fiber is expected to be applied in heat sensing.