scholarly journals Spin-flip Raman scattering of theΓ−Xmixed exciton in indirect band gap (In,Al)As/AlAs quantum dots

2014 ◽  
Vol 90 (12) ◽  
Author(s):  
J. Debus ◽  
T. S. Shamirzaev ◽  
D. Dunker ◽  
V. F. Sapega ◽  
E. L. Ivchenko ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Raman Scattering ◽  
Band Gap ◽  
Spin Flip ◽  
Indirect Band Gap

scholarly journals Optical orientation and alignment of excitons in direct and indirect band gap (In,Al)As/AlAs quantum dots with type-I band alignment

2019 ◽  
Vol 99 (19) ◽  
Author(s):  
J. Rautert ◽  
T. S. Shamirzaev ◽  
S. V. Nekrasov ◽  
D. R. Yakovlev ◽  
P. Klenovský ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Band Alignment ◽  
Type I ◽  
Optical Orientation ◽  
Indirect Band Gap

Phenomenological Modeling of Confined Phonon States in TMD Quantum Dots

MRS Advances ◽  
2018 ◽  
Vol 3 (6-7) ◽  
pp. 339-344 ◽  
Author(s):  
Lu Fang ◽  
Tamia Willliam ◽  
Kofi W. Adu ◽  
Mauricio Terrones
Keyword(s):  
Quantum Dots ◽  
Size Effect ◽  
Band Gap ◽  
Bulk Material ◽  
Single Layer ◽  
Interlayer Coupling ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Indirect Band Gap ◽  
Band Gap Tuning

ABSTRACTSeveral reports have shown band-gap tuning in TMDs, from indirect band gap in the bulk material to a direct gap in single layer due to the absence of interlayer coupling. This unique property stems from the modified electronic states. The phononic properties are extremely modified as well, due to layered effect and quantum size effect. There are several reports on layered effect; however, reports on the confined phonon states in these structures are limited. Thus, we present a preliminary studies of the confined phonon states in TMDs (WS2 and MoS2) quantum dots, and elucidate on the evolution of the phonon lineshape with diameter using a phenomenological model with an envelop function that truncates the phonon wave at the surface of the quantum dot. Furthermore, we delineate the layered effect from the quantum size effect in the phonon lineshape of WS2 and MoS2.

scholarly journals Towards a Germanium and Silicon Laser: The History and the Present

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 624
Author(s):  
Ivan Pelant ◽  
Kateřina Kůsová
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Room Temperature ◽  
Light Emitting ◽  
Recent Advances ◽  
The Sixties ◽  
Valence Bands ◽  
Indirect Band Gap ◽  
In The Beginning ◽  
Si Quantum Dots

Various theoretical as well as empirical considerations about how to achieve lasing between the conduction and valence bands in indirect band gap semiconductors (germanium and silicon) are reviewed, starting from the dawn of the laser epoch in the beginning of the sixties. While in Ge the room-temperature lasing under electrical pumping has recently been achieved, in Si this objective remains still illusory. The necessity of applying a slightly different approach in Si as opposed to Ge is stressed. Recent advances in the field are discussed, based in particular on light-emitting Si quantum dots.

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