中国物理B ›› 2017, Vol. 26 ›› Issue (8): 87103-087103.doi: 10.1088/1674-1056/26/8/087103

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Uniaxial strain-modulated electronic structures of CdX (X=S, Se, Te) from first-principles calculations: A comparison between bulk and nanowires

Linlin Xiang(相琳琳), Shenyuan Yang(杨身园)   

  1. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • 收稿日期:2017-03-10 修回日期:2017-05-04 出版日期:2017-08-05 发布日期:2017-08-05
  • 通讯作者: Shenyuan Yang E-mail:syyang@semi.ac.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204296 and 61427901) and the National Basic Research Program of China (Grant Nos. 2014CB643902 and 2013CB933304).

Uniaxial strain-modulated electronic structures of CdX (X=S, Se, Te) from first-principles calculations: A comparison between bulk and nanowires

Linlin Xiang(相琳琳), Shenyuan Yang(杨身园)   

  1. State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • Received:2017-03-10 Revised:2017-05-04 Online:2017-08-05 Published:2017-08-05
  • Contact: Shenyuan Yang E-mail:syyang@semi.ac.cn
  • About author:0.1088/1674-1056/26/8/
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11204296 and 61427901) and the National Basic Research Program of China (Grant Nos. 2014CB643902 and 2013CB933304).

摘要:

Using first-principles calculations based on density functional theory, we systematically study the structural deformation and electronic properties of wurtzite CdX (X=S, Se, Te) bulk and nanowires (NWs) under uniaxial [0001] strain. Due to the intrinsic shrinking strain induced by surface contraction, large NWs with {1010} facets have heavy hole (HH)-like valence band maximum (VBM) states, while NWs with {1120} facets have crystal hole (CH)-like VBM states. The external uniaxial strain induces an HH-CH band crossing at a critical strain for both bulk and NWs, resulting in nonlinear variations in band gap and hole effective mass at VBM. Unlike the bulk phase, the critical strain of NWs highly depends on the character of the VBM state in the unstrained case, which is closely related to the size and facet of NWs. The critical strain of bulk is at compressive range, while the critical strain of NWs with HH-like and CH-like VBM appears at compressive and tensile strain, respectively. Due to the HH-CH band crossing, the charge distribution of the VBM state in NWs can also be tuned by the external uniaxial strain. Despite the complication of the VBM state, the electron effective mass at conduction band minimum (CBM) of NWs shows a linear relation with the CBM-HH energy difference, the same as the bulk material.

关键词: first-principles calculations, electronic properties, semiconductor nanowires, uniaxial strain

Abstract:

Using first-principles calculations based on density functional theory, we systematically study the structural deformation and electronic properties of wurtzite CdX (X=S, Se, Te) bulk and nanowires (NWs) under uniaxial [0001] strain. Due to the intrinsic shrinking strain induced by surface contraction, large NWs with {1010} facets have heavy hole (HH)-like valence band maximum (VBM) states, while NWs with {1120} facets have crystal hole (CH)-like VBM states. The external uniaxial strain induces an HH-CH band crossing at a critical strain for both bulk and NWs, resulting in nonlinear variations in band gap and hole effective mass at VBM. Unlike the bulk phase, the critical strain of NWs highly depends on the character of the VBM state in the unstrained case, which is closely related to the size and facet of NWs. The critical strain of bulk is at compressive range, while the critical strain of NWs with HH-like and CH-like VBM appears at compressive and tensile strain, respectively. Due to the HH-CH band crossing, the charge distribution of the VBM state in NWs can also be tuned by the external uniaxial strain. Despite the complication of the VBM state, the electron effective mass at conduction band minimum (CBM) of NWs shows a linear relation with the CBM-HH energy difference, the same as the bulk material.

Key words: first-principles calculations, electronic properties, semiconductor nanowires, uniaxial strain

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

  • 71.15.Mb
73.22.-f (Electronic structure of nanoscale materials and related systems) 73.61.Ga (II-VI semiconductors) 77.80.bn (Strain and interface effects)