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Atomic Configuration of Dopant Atoms in ZnSe and ZnTe Determind by EXAFS

EXAFS 测定 ZnSe 和 ZnTe 中掺杂剂原子的原子构型

基本信息

批准号：
08650003
负责人：
AKIMOTO Katsuhiro
金额：
$ 1.34万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650003/
关键词：
II-VI Compound Semiconductor ZnSe ZnTe Carrier Compensation Doping Unipolar Semiconductor EXAFS Lattice Displacement

项目摘要

Atomic configuration and charge states of Cl or P in ZnSe and ZnTe were investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy and X-ray absorption near-edge structure (XANES) spectroscopy. By measuring Cl K-edge EXAFS,it was found that the Cl atoms in ZnSe are incorporated into four coordinated Se lattice sites, however in ZnTe, the Cl atoms are displaced from Te lattice sites, and probably moved toward [111] direction and from one-coordination. On the other hand, XANES spectra of P K-edge indicates the existence of two kinds of charge states in ZnSe. The carrir compensation mechanism seems to be different between Cl doped ZnTe and P doped ZnSe.Almost all II-VI compounds are unipolar materials. Though the cause of the unipolarity is not well understood yet, some models have been suggested such as 1) self-compensation by creating point defects, 2) solubility limit of impurities and 3) formation of DX centers by a displcement of dopant atoms. It is important to cl … More arify the atomic structure around dopant atoms to understand the cause of the unipolarity.The Cl doped ZnSe and ZnTe were grown on GaAs (100) substrate by molecular beam epitaxy. The atomic configuration of Cl dopant is about 1x10E19 cm-3 for both materials. The P doped materials were prepared by ion implantation into undoped ZnSe and undoped ZnTe grown on GaAs substrates by MBE.The dose of P ions were 4x10E14 cm-2 with 350 keV for both ZnSe and ZnTe. The EXAFS and XANES measurements were performed by fluorescence yield method at 100K.In the Cl doped ZnTe, two kinds of atomic distances, 0.24 and 0.32nm, between Cl and Zn were observed. The atomic distance between Zn and Te in ZnTe is 0.265nm, so it can be said that the Cl atom in ZnTe is not incorporated into the substiutional Te lattice site. The coordination number of Cl corresponding to shorter bond length (0.24nm) to that of longer one (0.32nm) is just 1 : 3. Therefore, Cl atoms may be displaced toward [111] direction and formed one-coordination.The XANES spectra of P doped ZnSe shows two absortion edges, indicating two kinds of charge states. The positive P ion may cause the carrier compensation in ZnSe. Less

利用扩展X射线吸收精细结构谱（EXAFS）和X射线吸收近边结构谱（XANES）研究了硒化锌（ZnSe）和碲化锌（ZnTe）中Cl和P的原子构型和电荷态。通过对Cl K边EXAFS的测量，发现在ZnSe中Cl原子被掺入到四配位的Se晶格中，而在ZnTe中Cl原子被从Te晶格中置换出来，可能从单配位向[111]方向移动。另一方面，P-K边的XANES谱表明ZnSe中存在两种电荷态。Cl掺杂的ZnTe和P掺杂的ZnSe的载流子补偿机制似乎不同，几乎所有的II-VI族化合物都是单极材料。虽然单极性的原因还没有很好地理解，但已经提出了一些模型，例如1）通过产生点缺陷的自补偿，2）杂质的溶解度限制和3）通过掺杂剂原子的相互作用形成DX中心。重要的是要CL ...更多信息利用分子束外延技术在GaAs（100）衬底上生长了Cl掺杂的ZnSe和ZnTe晶体。两种材料的Cl掺杂剂的原子构型均约为1 × 10 ~（19）cm ~（-3）。用分子束外延法在GaAs衬底上生长的未掺杂ZnSe和未掺杂ZnTe中注入P离子，P离子注入剂量均为4 × 10 ~（14）cm ~（-2），注入能量均为350 keV。用荧光产额法在100 K下进行了EXAFS和XANES测量，在Cl掺杂的ZnTe中，观察到Cl和Zn原子间的两种原子间距，分别为0.24和0.32nm。ZnTe中Zn和Te的原子间距为0.265nm，因此可以说ZnTe中的Cl原子没有掺入取代Te晶格位。较短键长（0.24nm）和较长键长（0.32nm）的Cl的配位数仅为1：3。结果表明，P掺杂的ZnSe的XANES谱具有两个吸收边，表明存在两种电荷状态。正P离子可引起ZnSe中载流子的补偿。少