Sulfur and Tellurium substituted Bismuth Selenide (BiSeSTe x = y = 0, 0.1, 0.15, 0.2) quaternary alloy crystals were synthesized by using vertical Bridgman technique. Energy dispersive analysis of X-rays confirmed elemental composition and purity of the grown crystals. Field emission scanning electron microscopy showed that the growth of crystals has occurred by layer growth mechanism. Rhombohedral crystal structure is validated through analysis of powder X-ray diffraction pattern. Thermoelectric parameters such as electrical conductivity, Seebeck coefficient and thermal conductivity were calculated from 303 K to 773 K and from that power factor as well as figure of merit have been determined for all grown crystals. Electrical conductivity significantly increased due to Sulfur and Tellurium incorporation and maximum value obtained is 147.72 S/cm at 503 K for BiSeSTe. Seebeck coefficient and thermal conductivity showed decrement with incorporation of Sulfur and Tellurium. Reduction in thermal conductivity and enhancement in electrical conductivity resulted in the improvement of figure of merit. Sulfur and Tellurium substitution showed considerable improvement in from 0.31 (533 K) for pristine BiSe to 1.28 (523 K) for BiSeSTe

中文翻译：

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通过硫和碲的取代增强硒化铋晶体的热电行为

采用垂直布里奇曼技术合成了硫和碲取代的硒化铋(BiSeSTe x = y = 0, 0.1, 0.15, 0.2)四元合金晶体。 X 射线能量色散分析证实了生长晶体的元素组成和纯度。场发射扫描电子显微镜表明晶体的生长是通过层生长机制发生的。通过粉末 X 射线衍射图分析验证了菱面体晶体结构。计算了 303 K 至 773 K 范围内的电导率、塞贝克系数和热导率等热电参数，并根据该功率因数和品质因数确定了所有生长的晶体。由于硫和碲的加入，电导率显着增加，BiSeSTe 在 503 K 时获得的最大值为 147.72 S/cm。塞贝克系数和热导率随着硫和碲的加入而降低。热导率的降低和电导率的提高导致品质因数的提高。硫和碲替代显示出相当大的改进，从原始 BiSe 的 0.31 (533 K) 到 BiSeSTe 的 1.28 (523 K)