Aliovalent substitutions of the 2D layered semiconductor GeAs
Aliovalent substitutions of the 2D layered semiconductor GeAs
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DOI：
10.1016/j.jssc.2019.05.016
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发表时间：
2019-08-01
影响因子：
3.3
通讯作者：
Kovnir, Kirill
中科院分区：
文献类型：
--
作者：
Lee, Shannon;Owens-Baird, Bryan;Kovnir, Kirill
层状四元磷属化合物由于其各向异性的晶体结构和层间弱的货车范德华相互作用而显示出作为热电体（TE）的前景。二元GeAs是一种p型半导体，具有0.57 eV的窄间接带隙和高Seebeck系数（类似于300 K时的250 μ V/K）。这项工作探讨的限制aliovalent取代的GeAs修改载流子浓度。合成了GaxGe_（1-x）As（x = 0.005，0.01，0.02）和GeAs_（1-y）Sey（y = 0.01，0.02，0.03，0.05）样品，研究了该体系的结构-性能关系。通过Ga取代对GeAs进行空穴掺杂，增加了载流子浓度，导致电阻率和塞贝克系数均降低。硒取代的样品表现出更复杂的行为有关的缺陷化学。总体而言，热电功率因数（S-2/p）显着增强（高达89%）为Ga 0.005Ge 0.995砷相比，原始的GeAs。
Layered tetrel pnictides have shown promise as thermoelectrics (TEs) due to their anisotropic crystal structure and weak van der Waals interactions between layers. The binary GeAs is a p-type semiconductor with a narrow indirect bandgap of 0.57 eV and a high Seebeck coefficient (similar to 250 mu V/K at 300 K). This work probes the limits of the aliovalent substitutions of GeAs to modify charge carrier concentration. GaxGe1-x As (x = 0.005, 0.01, and 0.02) and GeAs1-ySey (y = 0.01, 0.02, 0.03, and 0.05) samples were synthesized to study the structure-property relationships in this system. Hole doping of GeAs via Ga-substitution increases carrier concentration resulting in the decrease in both resistivity and Seebeck coefficient. Se-substituted samples show more complex behavior related to defect chemistry. Overall, the thermoelectric power factor (S-2/p) was significantly enhanced (up to 89%) for Ga0.005Ge0.995As as compared to pristine GeAs.