Enhanced photoluminescence due to lateral ordering of GeSi quantum dots on patterned Si(001) substrates.
Multilayer ordered GeSi quantum dots (QDs) with thin Si spacers were obtained via self-assembly on pit-patterned Si(001) substrates. The lateral ordering of GeSi QDs predetermined by the periodic pit pattern results in remarkably improved size uniformity in comparison with random QDs on flat substrates. A much stronger and narrower photoluminescence (PL) peak from ordered QDs were observed than that from random ones, particularly at high excitation power. Such enhanced PL signal was attributed to the high density of states and the uniform distribution of excitons in the ordered and uniform QDs, which can efficiently suppress the Auger effect and the Coulomb screening effect. Moreover, anomalous narrowing of the PL peak from the ordered QDs with the excitation power was observed, which was explained in terms of distributed feedback associated with the periodic stacked GeSi QDs.
Chen
Yanwu
Y
Surface Physics Laboratory (National Key Laboratory), Fudan University, Shanghai, People's Republic of China.
Pan
Bingying
B
Nie
Tianxiao
T
Chen
Peixuan
P
Lu
Fang
F
Jiang
Zuimin
Z
Zhong
Zhenyang
Z
D004563:Electrochemistry; D005857:Germanium / Q000737:chemistry*; D049449:Luminescence; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots; D012825:Silicon / Q000737:chemistry*
D005857:Germanium; D012825:Silicon