Khromov S, Gregorius D, Schiller R, Lösch J, Wahl M, Kopnarski M, Amano H, Monemar B, Hultman L, Pozina G
Department of Physics, Chemistry, and Biology (IFM), Linköping University, S-581 83 Linköping, Sweden.
Nanotechnology. 2014 Jul 11;25(27):275701. doi: 10.1088/0957-4484/25/27/275701. Epub 2014 Jun 24.
Atom probe tomography studies on highly Mg-doped homoepitaxial GaN (0001) layers with concentrations of 5 × 10(19) cm(-3) and 1 × 10(20) cm(-3) were performed. Mg cluster formation was observed only in the higher doped sample whereas in the lower doped sample the Mg distribution was homogeneous. CL measurements have shown that the emission normally attributed to stacking faults was only present in the lower doped layers (with Mg concentration of ∼5 × 10(19) cm(-3) or less), but absent in the higher doped layer, where Mg clusters were detected. Mg clusters are proposed to produce a screening effect, thereby destroying the exciton binding on the SFs and thus rendering them optically inactive.
对镁浓度为5×10¹⁹ cm⁻³和1×10²⁰ cm⁻³的高镁掺杂同质外延GaN(0001)层进行了原子探针断层扫描研究。仅在高掺杂样品中观察到镁团簇的形成，而在低掺杂样品中镁分布是均匀的。阴极发光测量表明，通常归因于堆垛层错的发射仅存在于低掺杂层（镁浓度约为5×10¹⁹ cm⁻³或更低），而在检测到镁团簇的高掺杂层中不存在。有人提出镁团簇会产生一种屏蔽效应，从而破坏堆垛层错上的激子束缚，进而使其光学上不活跃。
