物理学报
物理學報
물이학보
2015年
8期
087102-1-087102-8
,共1页
电荷转移%少层MoS2%层间静电作用%功函数
電荷轉移%少層MoS2%層間靜電作用%功函數
전하전이%소층MoS2%층간정전작용%공함수
charge transfer%few-layer MoS2%interlayer electrostatic interaction%work function
基于第一性原理计算，研究了Li掺杂的少层(1—3层) MoS2的电荷分布，并与石墨片和BN片的电荷分布特征进行了比较。与石墨片和BN片相同的是：电荷转移的大部分只发生在Li与最靠近Li的第一层MoS2之间。然而，第二层和第三层MoS2也能获得10%的转移电荷，而石墨片和BN片的第二层和第三层得不到2%的电荷。结合静电能和功函数的分析可知， MoS2、石墨片和BN片的电荷分布主要由层间的静电相互作用和功函数来决定。这些研究结果对于揭示具有多层结构的电荷分布特征及其电子器件的设计提供了理论支持。
基于第一性原理計算，研究瞭Li摻雜的少層(1—3層) MoS2的電荷分佈，併與石墨片和BN片的電荷分佈特徵進行瞭比較。與石墨片和BN片相同的是：電荷轉移的大部分隻髮生在Li與最靠近Li的第一層MoS2之間。然而，第二層和第三層MoS2也能穫得10%的轉移電荷，而石墨片和BN片的第二層和第三層得不到2%的電荷。結閤靜電能和功函數的分析可知， MoS2、石墨片和BN片的電荷分佈主要由層間的靜電相互作用和功函數來決定。這些研究結果對于揭示具有多層結構的電荷分佈特徵及其電子器件的設計提供瞭理論支持。
기우제일성원리계산，연구료Li참잡적소층(1—3층) MoS2적전하분포，병여석묵편화BN편적전하분포특정진행료비교。여석묵편화BN편상동적시：전하전이적대부분지발생재Li여최고근Li적제일층MoS2지간。연이，제이층화제삼층MoS2야능획득10%적전이전하，이석묵편화BN편적제이층화제삼층득불도2%적전하。결합정전능화공함수적분석가지， MoS2、석묵편화BN편적전하분포주요유층간적정전상호작용화공함수래결정。저사연구결과대우게시구유다층결구적전하분포특정급기전자기건적설계제공료이론지지。
According to first-principles calculation, we study the charge distribution of Li-doped few-layer (1–3 layers) MoS2 and compare it with the results of graphene and BN. It is found that the stable adsorption sites of Li are the top (Mo) site for MoS2 layer, and the hexagonal center for graphene and BN layers. Band structures of pristine MoS2 show that single-layer MoS2 is a direct band gap semiconductor while few-layer MoS2 is an indirect one. As MoS2 is doped, the Fermi level will shift to the conduction band, indicating a charge transfer between Li and MoS2. The charge transfer takes place mostly between Li and the topmost MoS2 layer, which is very similar to that happening between graphene and BN. However, the second and third layer of MoS2, which are far from Li, can acquire about 10% of transferred charges. In contrast, the second and third layer obtain no more than 2% of charges for graphene and BN. Based on the electrostatic theory, we derive for both double and triple layers the formulas of electrostatic energy, which show clearly that only charge transfer between Li and the topmost layer will give the lowest electrostatic energy. Moreover, we calculate the work functions of pristine MoS2, graphene and BN, and find that, despite similar work functions of MoS2 and BN, the larger band gap of BN will make charge transfer between Li and BN harder. The analyses of electrostatic energy and work function show that the charge distribution is dominated by both interlayer electrostatic interaction and work function of material. It is expected that the above results could be helpful for doping layered structures and designing devices.
