Two Step Sintering Method Research Based On The Cuinse₂Alloy Powder

For the moment, the research of copper indium selenium （patent CuInSe₂,abbreviations for CIS） solar cells materials are more focused on the production processand the optimization of the crystal structure of the absorbing layer CIS film. Theresearch of the preparation of the CIS powder is less, the domestic literature is rarelyreported. The research of the CIS powder materials for the absorbing layer of the solarcell film can decrease the cost of manufacturing and is expected to open up a new solarbattery domain.By using the tube type vacuum furnace, bronze （Cu） powder, indium （In） powder,selenium （Se） powder （raw materials for the mole ratio1:1:2） as raw material, argonatmosphere protection, the CIS powder was produced by two steps sintering with thestandard chemical measurement.In the first sintering step, the Cu powder and In powder mixture （both Moore ratioof1:1） sintered In950℃, Cu-In compound powder was produced.This elements ratioof powder gradually become1:1with the extension of the reaction time. Reacts is notcompletely if it was sintering in insufficient time, the final product has In surplus.In the Step2sintering process, the Cu-In compound powder sintered with Sepowder sintered after mixing, sintering temperature at550℃in argon atmosphere,sintering time is3h,5h and10h. We can compare with the the influence inmicrostructure of final product sintering in different time.We used X ray diffraction analyzer for the content and phase analysis, the analysisresults showed that the the CIS product of standard chemical measurement can beprepared by two step sintering process.The product is single phase with chalcopyritetype crystal structure. The microstructure of the product with the difference sinteringtime shows a difference. The extension time of sintering help grain refined. Althoughelements ratio of the Cu-In product In the first step preparation is not for the1-1, butthis is no impact for the composition of the subsequent prepared CuInSe₂powder. Evenif Cu powder and In powder not combined fully, the fianl product is still a relativelypure single-phase chalcopyrite type CuInSe₂powder. Using scanning electronmicroscope SEM observe the surface morphology of the sample, and the results showthat CIS sintering product contains a lot of hole, the product is loose, the reactionsintering produce massive uneven surface,the tiny granule.Through the energyspectrum analyzer EDS analyses the chemical composition of products, we can see that the experiment in the product of preparation out both constituencies analysis or clickon analysis, the chemical measurement is roughly about1:1:2. This XRD analysisresults are in agreement. This also verified through the two steps can be prepared forthe heat sintering elements of the CIS product than measurement, the synchronousthermal analyzer on the preparation process of chemical reaction process is analyzed.This experiment used two steps to sintering preparation which is a improvement ofthe one step sintering of the CIS. In the one step sintering preparation, Cu powder, Inpowder and Se powder put into quartz tube welding seam after mixing. after heated to950℃, carries on the reaction. The method has some shortage,950℃heated, more thanthe boiling point of melting Se powder, make selenium volatilization, cause reactionwas not complete. At the same time selenium steam toxic, if not handled properly itwill be harm for the experiment person and be harm for the environment. Quartztubevacuum weld after operation is relatively complex, and quartz tube fragile, the price iscorundum tube expensive. This experiment used two step sintering process is toovercome the shortcomings. The temperature of Two step reaction controled below theboiling point of the following elements, to avoid the expansion of the volatilecompounds not completely and brought harm to the person, the environment; Thesintering experiment not only reduce the cost of corundum pipe, and the experimentthe operability, repeatability is greatly increased.The analysis results show that:To Cu powder, In powder, Se powder as raw materials by two-step heat sinteringcan be prepared with chemical measurement than the standard of the CIS powder. TheXRD map and standard product almost the same map, product structure forchalcopyrite type.