Dopant-induced indirect-direct transition and semiconductor-semimetal transition of bilayer SnSe
Dopant-induced indirect-direct transition and semiconductor-semimetal transition of bilayer SnSe
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DOI：
10.1063/1.5128337
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发表时间：
2019-12
影响因子：
3.2
通讯作者：
Hansika I. Sirikumara;Mahir Morshed;Casey Jameson;T. Jayasekera
中科院分区：
文献类型：
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作者：
Hansika I. Sirikumara;Mahir Morshed;Casey Jameson;T. Jayasekera
硒化锡（SnSe）是一种层状半导体，是迄今为止最好的热电材料。少层硒化锡对外部条件如应变、压力或温度高度敏感。SnSe的晶体结构为正交结构，原子呈手风琴状排列，层内相互作用无键。据报道，块状和少层原始SnSe具有间接电子带隙。基于第一性原理密度泛函理论计算的结果，我们发现取代化学掺杂双层SnSe可以发生两个主要的结构变化。取代化学掺杂可以控制双层SnSe层间相互作用的方向性，从而导致电子带隙的间接直接跃迁。我们的研究结果还表明，较大的掺杂原子可以将非键的层内相互作用转化为共价键。原子轨道重叠的这种增加可能导致半导体-半金属跃迁。硒化锡（SnSe）是一种层状半导体，是迄今为止最好的热电材料。少层硒化锡对外部条件如应变、压力或温度高度敏感。SnSe的晶体结构为正交结构，原子呈手风琴状排列，层内相互作用无键。据报道，块状和少层原始SnSe具有间接电子带隙。基于第一性原理密度泛函理论计算的结果，我们发现取代化学掺杂双层SnSe可以发生两个主要的结构变化。取代化学掺杂可以控制双层SnSe层间相互作用的方向性，从而导致电子带隙的间接直接跃迁。我们的研究结果还表明，较大的掺杂原子可以将非键的层内相互作用转化为共价键。原子轨道重叠的这种增加可能会导致半导体-半半…
Tin selenide (SnSe) is a layered semiconductor, which is reported to be the best thermoelectric material to date. Few-layer tin selenide is highly sensitive to external conditions such as strain, pressure, or temperature. Crystal structure of SnSe is orthorhombic, where atoms are arranged in an accordionlike structure with nonbonding intralayer interactions. Bulk and few-layer pristine SnSe are reported to have indirect electron bandgaps. Based on the results from first-principles density functional theory calculations, we show that two major structural changes can happen upon substitutional chemical doping of bilayer SnSe. Substitutional chemical doping can manipulate the directionality of interlayer interactions of bilayer SnSe, which results in an indirect-direct transition of the electronic bandgap. Our results also suggest that larger dopant atoms can convert the nonbonding intralayer interactions to covalent bonding. Such an increase in the atomic orbital overlap may result in a semiconductor-semimetal transition.Tin selenide (SnSe) is a layered semiconductor, which is reported to be the best thermoelectric material to date. Few-layer tin selenide is highly sensitive to external conditions such as strain, pressure, or temperature. Crystal structure of SnSe is orthorhombic, where atoms are arranged in an accordionlike structure with nonbonding intralayer interactions. Bulk and few-layer pristine SnSe are reported to have indirect electron bandgaps. Based on the results from first-principles density functional theory calculations, we show that two major structural changes can happen upon substitutional chemical doping of bilayer SnSe. Substitutional chemical doping can manipulate the directionality of interlayer interactions of bilayer SnSe, which results in an indirect-direct transition of the electronic bandgap. Our results also suggest that larger dopant atoms can convert the nonbonding intralayer interactions to covalent bonding. Such an increase in the atomic orbital overlap may result in a semiconductor-semime...