Engineering the Effective p-Type Dopant in GaAs/InAs Core鈥揝hell Nanowires with Surface Dangling Bonds

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• 作者：Changsheng Song ; Jiqing Wang ; Zhixiang Zhang ; Huibing Mao ; Qiang Zhao ; Pingxiong Yang ; Huaizhong Xing
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：October 30, 2014
• 年：2014
• 卷：118
• 期：43
• 页码：25209-25214
• 全文大小：404K
• ISSN：1932-7455

文摘

Using first-principles calculation based on density-functional theory, we investigated the effect of surface dangling bond on p-type doping mechanism and the electronic structures in wurtzite (WZ) and zinc blende (ZB) GaAs/InAs core鈥搒hell nanowires (NWs) along the [0001] and [111] directions, respectively. The results of the formation energies show that the surface dangling bond of the In atom is a kind of stable defect. Both in WZ and ZB core鈥搒hell NWs, we found it is easier and more stable to realize dopant in the GaAs core. Moreover, the position of Cd impurity plays a key role in the formation of p-type nanowires. The farther the distance between the impurity and the surface dangling In atom, the easier it is to form the p-type characteristic of the nanowires. In particular, it shows an intrinsic behavior when doping the Cd impurity near the surface dangling bond. The surface dangling bonds have an ability to capture the holes from the neighbor doping impurity, resulting in the deactivation of dopants. Meanwhile, the transfer of hole moves the valence band down to the lower energy levels and even can lead to a band anticrossing phenomenon in the conduction band. Our results highlight a new physical coupling between the doped state and surface dangling bonds in GaAs/InAs core鈥搒hell NWs, and open a new opportunity for the development of tailoring nanoscale electronic properties.