TEMPERATURE AND HYDROSTATIC PRESSURE DEPENDENCE OF SUBBAND STRUCTURE IN GaAs/AlxGa1−xAs MULTIPLE QUANTUM WELL

1990 ◽  
Vol 04 (14) ◽  
pp. 917-920 ◽  
Author(s):  
Y. FU

The temperature and hydrostatic pressure dependence of GaAs/AlxGa1−xAs multiple quantum well subband structures has been examined theoretically. Such effects on the subband energy measured from the corresponding band optimum are negligible, and therefore, the temperature and the hydrostatic pressure coefficients of these multiple quantum wells are dominated by those coefficients of the bulk GaAs bandgap.

1995 ◽  
Vol 406 ◽  
Author(s):  
J. Q. Zhang ◽  
Z. X. Liu ◽  
Z. P. Wang ◽  
H. X. Han ◽  
G. H. Li ◽  
...  

AbstractThe photoluminescence and Raman scattering of {|(CdSe)1 (ZnSe)3|14-(ZnSe)130} × 5 multiple quantum well structure have been investigated at 77 K and under hydrostatic pressure up to 7 GPa. Resonant excitations have been accomplished by turning the electronic levels under hydrostatic high pressure. Two kind of excitons and ZnSe-like LO phonon modes as well as their pressure behavior are presented.


2000 ◽  
Vol 639 ◽  
Author(s):  
E.M. Goldys ◽  
M. Godlewski ◽  
M.R. Phillips ◽  
A.A. Toropov

ABSTRACTWe have examined multiple quantum well AlGaN/GaN structures with several quantum wells of varying widths. The structures had strain-free quantum wells and strained barriers. Strong piezoelectric fields in these structures led to a large red shift of the PL emission energies and long decay times were also observed. While the peak energies could be modelled using the effective mass approximation, the calculated free exciton radiative lifetimes were much shorter than those observed in experiments, indicating an alternative recombination mechanism, tentatively attributed to localised excitons. Cathodoluminescence depth profiling revealed an unusually small penetration range of electrons suggesting that electron-hole pairs preferentially remain within the multiple quantum well region due to the existing electric fields. Spatial fluctuations of the cathodoluminescence intensity were also observed.


1985 ◽  
Vol 56 ◽  
Author(s):  
H. NEFF ◽  
K. J. BACHMANN ◽  
W. D. LAIDIG

AbstractEmploying temperature dependent photoconductivity, photoluminescence and photoreflectivity measurements, we have analyzed a GaAs-AlAs multiple quantum well. The above optical techniques clearly resolve the fundamental inter-subband transitions, including heavy hole-light hole splittings. At T < 60K an anomalously high photoconductivity was discovered below the direct inter-subband transitions and is attributed tentatively to the presence of extrinsic interface states within the bandgap. For T > l00K the fundamental indirect transition was discovered and associated with LO (L) - phonon absorption.


1994 ◽  
Vol 299 ◽  
Author(s):  
F. Szmulowicz ◽  
M. O. Manasreh ◽  
C. Kutsche ◽  
C. E. Stutz

AbstractIntersubband transitions in a series of well-doped ([Si] = 2.0×1018cm−3) In0.07Ga0.93As/Al0.4Ga0.6As multiple quantum well samples were studied as a function of the well width by using the optical absorption technique. A single intersubband transition is observed in samples in which the Fermi energy level is between the ground and the first excited states in the quantum well. On the other hand, two intersubband transitions were recorded in samples where the Fermi energy level lies between the first and the second excited states. These two intersubband transitions were attributed to ground-to-first excited states and first-to-second excited states transitions. The energy separation between the latter two intersubband transitions was found to increase as the well width is increased. The fact that two intersubband transitions were observed in certain samples may suggest that specially designed quantum wells can be used for two color long wavelength infrared detectors.


1992 ◽  
Vol 281 ◽  
Author(s):  
F. G. Johnson ◽  
G. W. Wicks ◽  
R. E. Viturro ◽  
R. Laforce

ABSTRACTWe report on the first growth of GaAs/Ga0.5In0.5P heterostructures by conventional molecular beam epitaxy using solid-source valved crackers to supply both the arsenic and the phosphorus fluxes. By regulating the group V fluxes with the cracker needle valves, arsenide-phosphide heterostructures were successfully grown with virtually no group V intermixing between layers. For comparison, similar heterostructure samples were grown using only the mechanical shutters to switch between group V fluxes, and the resulting layers were severely intermixed. The amount of group V intermixing was shown to be independent of whether As2 or As4 fluxes were used to grow the layers. A GaAs/Ga0.5In0.5P multiple quantum well sample was also grown using the valved crackers. Photoluminescence peaks were clearly observed from 40 Å, 80 Å, and 300 Å GaAs quantum wells, but no luminescence was detected from a 20 Å well. An 80Å GaAs/ 80Å Ga0.5In0.5P superlattice was grown, and superlattice satellite peaks were observed in the X-ray rocking curves. The appearance of misfit dislocations suggests localized intermixing at the interfaces.


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