Effect Of Anneal And Microstructure On Characteristic Of SnS Film

SnS is the substance which adapts well to light absorb layer of solar battery for its excellently physical and chemic characteristic. How to make its performance better and how to improve its photon-to-current efficiency of cell has become an emphasis which is being studied by people recently.In this text, for one hand, SnS films produced by SILAR were dealed with annealing at different temperature. The phase transformation of sample aroused by annealing and its infrared absorb characteristic after heat treatment were studied. On the other hand, the structure of porous SnS produced by CBD and compact SnS came from SILAR was compared. the relation between peak intensity,peak length and microstructure was analyzed.The crystallization of films was studied by XRD. It has been found that annealing,substrate and ion concentration can change the crystallization. In the course of anneal from 200℃to 300℃, peak intensity of XRD of SnS films increase at first, and then decrease again. It is thus tentatively assumed that 250℃is the best one which is in favor of crystallization of SnS films. It has also been shown SnS is rhombic after annealing and has good crystallization with preferential orientation along (021). Crystallite grows up when being annealed. With increase of Sn2+ concentration and use of ITO substrate this trend along(101) become obvious. Besides, crystallization of sample produced by SnCl2 solution of 0.1mol/l is better than that by SnCl2 solution of 0.2mol/l and glass substrate is more propitious to crystallization of SnS films than ITO substrate. The result of IR reveals SnS has no absorb peak in middle-far infrared region, But intervention of impurities when annealing arosed absorb peak in IR. Test of SEM and PL shows that microstructure of sample has some influence on its photoluminescence mechanism. Crystals produced by CBD are like needle which are tied to make a porous shape of net. However, samples produced by SILAR are near sphericity which have level and compact surface. The two types of samples have all a peak perching in 880.3nm, but microstructure difference leads to that peak intensity produced by CBD is stronger than that by SILAR. The peak is regarded to be caused by transition of band gap. In addition, two feeble peaks located in 720.5nm and 806.3nm respectively coming from the above methods are regarded to be caused by the effect of surface state with its matter in light emission, which also has relation with microstructure of sample.