scholarly journals Contribution of top barrier materials to high mobility in near-surface InAs quantum wells grown on GaSb(001)

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Joon Sue Lee ◽  
Borzoyeh Shojaei ◽  
Mihir Pendharkar ◽  
Mayer Feldman ◽  
Kunal Mukherjee ◽  
...  
2001 ◽  
Vol 15 (17n19) ◽  
pp. 683-687
Author(s):  
A. SILVA-CASTILLO ◽  
F. PEREZ-RODRIGUEZ

We have applied the 45° reflectometry for the first time to study exciton-polaritons in quantum wells. The 45° reflectometry is a new polarization-modulation technique, which is based on the measurement of the difference [Formula: see text] between the p-polarization reflectivity (Rp) and the squared s-polarization reflectivity [Formula: see text] at an angle of incidence of 45°. We show that [Formula: see text] spectra may provide qualitatively new information on the exciton-polariton modes in a quantum well. These optical spectra turn out to be very sensitive to the zeros of the dielectric function along the quantum-well growth direction and, therefore, allow to identify the resonances associated with the Z exciton-polariton mode. We demonstrate that 45° reflectometry could be a powerful tool for studying Z exciton-polariton modes in near-surface quantum wells, which are difficult to observe in simple spectra of reflectivity Rp


1998 ◽  
Vol 84 (4) ◽  
pp. 2112-2122 ◽  
Author(s):  
P. Ramvall ◽  
N. Carlsson ◽  
P. Omling ◽  
L. Samuelson ◽  
W. Seifert ◽  
...  

2021 ◽  
Vol 82 (3) ◽  
pp. 219-221
Author(s):  
Sava Kolev

Radon gas has high mobility and is driven by advection and diffusion with the soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. Hence the radon potential of the area could be dependent on not only geology as a constant source of radon but also from the changes of the saturation state of the ground. The loess complex, characterized by its permeability and usual state of unsaturation, covers 10% of the Bulgarian territory. The study deals with the principles of unsaturated domain modeling. An attempt of generic vertical infiltration model coinciding with the most upper part of loess vadose zone was performed.


Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина

Abstract The specific features of the interaction of charged particles with polar optical phonons have been studied theoretically for quantum wells with the barriers that are asymmetric in their dielectric properties. It is shown that the interaction with interface phonon modes makes the greatest contribution in narrow quantum wells. The parameters of the electron-phonon interaction were found for the cases of different values of the phonon frequencies in the barrier materials. It turned out that a significant (by almost an order of magnitude) change in the parameters of the electron-phonon interaction can occur in such structures. This makes it possible, in principle, to trace the transition from weak to strong interactions in quantum wells of the same type but with different compositions of barrier materials. The conditions are found under which an enhancement of the electron-phonon interaction is possible in an asymmetric structure in comparison with a symmetric one with the barriers of the same composition.


2014 ◽  
Vol 23 (03n04) ◽  
pp. 1450015 ◽  
Author(s):  
Andrew Greene ◽  
Shailesh Madisetti ◽  
Michael Yakimov ◽  
Vadim Tokranov ◽  
Serge Oktyabrsky

Alternative channel materials with superior transport properties over conventional silicon based systems are required for supply voltage scaling in CMOS circuits. Group III- Sb 's are a candidate for high mobility p-channel applications due to a low hole effective mass, large injection velocity in scaled devices and the ability to achieve enhanced hole mobility in strained quantum wells (QW). Multiple challenges in antimonide MOSFET development are assessed and developed technologies were implemented into p-channel MOSFET fabrication with a low thermal processing budget of 350°C. These challenges include growth of “bulk” GaSb and bi-axial compressively strained In x Ga 1-x Sb QW channels on lattice mismatched GaAs substrates, reduction of interface trap state density (Dit) at the III- Sb /high-k oxide interface and avoiding ion implanted source and drain contacts with high temperature activation annealing. A “self-aligned” single mask p-channel MOSFET fabrication process was developed on buried In 0.36 Ga 0.64 Sb QW channels using intermetallic source and drain contacts. The first “gate-last” MOSFET process on In 0.36 Ga 0.64 Sb QW channels with pre-grown epitaxial p++- GaSb contacts is demonstrated. InAs has been proven to be an excellent etch stop layer when using an optimized tetramethylammonium hydroxide (TMAH) etch of p++- GaSb to prevent InGaSb QW damage.


2019 ◽  
Vol 970 ◽  
pp. 276-282
Author(s):  
Yury Borodin ◽  
Anastasia Mantina

Superlattice formation in thin layers of oxidizing crystals and the effect of near-surface proton saturation on structure ordering, formation and periodical distribution of quantum wells have been discussed. The paper shows, it is necessary to develop non-Euclidean approach to the crystal’s internal geometry and consider, in consecutive order, the question of the four-dimentional Riemannian space into three-dimentional Eucliden space interpretation (RE interpretation).


1999 ◽  
Vol 607 ◽  
Author(s):  
Seung-Woong Lee ◽  
Kazuhiko Hirakawa ◽  
Yozo Shimada

AbstractWe have designed and fabricated a quantum dot infrared photodetector which utilizes lateral transport of photoexcited carriers in the modulation-doped A1GaAs/GaAs two-dimensional (2D) channels. A broad photocurrent signal has been observed in the photon energy range of 100–300 meV due to bound-to-continuum intersubband absorption of normal incidence radiation in the self-assembled InAs quantum dots. A peak responsivity was as high as 2.3 A/W. The high responsivity is realized mainly by a high mobility and a long lifetime of photoexcited carriers in the modulation-doped 2D channels. Furthermore, we found that this device has high operation temperature and very high photoconductive gain.


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