Persson Clas, Platzer-Björkman Charlotte, Malmström Jonas, Törndahl Tobias, Edoff Marika
Department of Materials Science and Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Phys Rev Lett. 2006 Oct 6;97(14):146403. doi: 10.1103/PhysRevLett.97.146403. Epub 2006 Oct 4.
Photoelectron spectroscopy, optical characterization, and density functional calculations of ZnO1-xSx reveal that the valence-band (VB) offset E(v)(x) increases strongly for small S content, whereas the conduction-band edge E(c)(x) increases only weakly. This is explained as the formation of local ZnS-like bonds in the ZnO host, which mainly affects the VB edge and thereby narrows the energy gap: E(g)(x=0.28) approximately E(g)(ZnO)-0.6 eV. The low-energy absorption tail is a direct Gamma(v)-->Gamma(c) transition from ZnS-like VB. The VB bowing can be utilized to enhance p-type N(O) doping with lower formation energy DeltaH(f) and shallower acceptor state in the ZnO-like alloys.
对ZnO1-xSx进行的光电子能谱、光学表征和密度泛函计算表明，对于低硫含量，价带（VB）偏移E(v)(x)强烈增加，而导带边缘E(c)(x)仅微弱增加。这被解释为在ZnO主体中形成了类似局部ZnS的键，这主要影响VB边缘，从而缩小了能隙：E(g)(x = 0.28) 约等于 E(g)(ZnO) - 0.6 eV。低能吸收尾是从类似ZnS的VB直接发生的Gamma(v)-->Gamma(c)跃迁。VB弯曲可用于增强p型N(O)掺杂，在类似ZnO的合金中具有更低的形成能DeltaH(f)和更浅的受主态。
