Resonant-photon tunneling effect at 1.5 micron observed in GaAs/AlGaAs multi-layered structure containing InGaSb quantum dots

2005 ◽  
Author(s):  
Naokatsu Yamamoto
Keyword(s):  
Quantum Dots ◽  
Layered Structure ◽  
Tunneling Effect ◽  
Photon Tunneling

PHOTOLUMINESCENCE OF ULTRA SMALL InAs/GaAs QUANTUM DOTS

2005 ◽  
Vol 19 (18) ◽  
pp. 907-917 ◽  
Author(s):  
Y. G. LIN ◽  
C. H. WU ◽  
S. L. TYAN ◽  
S. D. LIN ◽  
C. P. LEE
Keyword(s):  
Quantum Dots ◽  
Phonon Scattering ◽  
Transition Energy ◽  
Tunneling Effect ◽  
Energy Separation ◽  
Hole State ◽  
Temperature Dependent ◽  
Pl Spectra ◽  
Shape Dependence ◽  
Electron And Hole States

The InAs/GaAs quantum dots (QDs) with a baselength of less than 10 nm are studied by the excitation-, temperature-dependent and magneto-photoluminescence (PL). The baselengths of the QDs, calculated by the PL ground state transition energy and estimated by magneto-PL spectra, are in agreement with the result of atomic force microscopy measurements. By means of the excitation-dependent PL, we demonstrate that only the ground electron and hole states exist when the baselength of the QDs is smaller than about 7.3 nm, whereas the larger dots with a baselength of about 8.7 nm will give rise to one excited hole state. The measured energy separation between the ground and the excited hole states is in good agreement with the theoretical calculation. The transition energy in temperature-dependent PL spectra shows a rapid redshift as the temperature is higher than the critical temperature. The redshift rate is about 2.8 and 2.5 times larger than the values calculated by Varshni's law for small and large dots respectively. The higher redshift rate can be explained by the stronger tunneling effect. In addition, the PL linewidths show a V-shape dependence with the temperature. This behavior could be well described as a tunneling and electron-phonon scattering effect.

Enhanced detectivity of PbS quantum dots infrared photodetector by introducing the tunneling effect of PMMA

2020 ◽  
Author(s):  
Zhenzhen Ma ◽  
Jiahui Li ◽  
Yating Zhang ◽  
Hongliang Zhao ◽  
Qingyan Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Tunneling Effect ◽  
Infrared Photodetector ◽  
Pbs Quantum Dots

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

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