New quasi-atomic nanostructures containing exciton quasimolecules and exciton quasicrystals: theory
In review, deals with the theory of exciton quasimolecules in a nanoheterostructures. It has been found that the formation of a exciton quasimolecule in a nanoheterostructures made up of aluminum oxide quantum dots synthesized in a dielectric matrix is of threshold character and can occur in a nanosystem where the distance D between the surfaces of quantum dots is given by the condition . The existence of such distance arises from quantum size effects in which the decrease in the energies of interaction of the electrons and holes entering into the Hamiltonian of the “exciton molecule” with decrease of the distance D between the surfaces of the QD cannot compensate for the increase in the kinetic energy of the electrons and holes. At larger distances D between the surfaces of quantum dots: the biexciton breaks down into two excitons (consisting of spatially separated electrons and holes), localized over QD surfaces.
It was shown that the convergence of two quantum dots up to a certain critical value between surfaces of quantum dot lead to overlapping of electron orbitals of superatoms and the emergence of exchange interactions. In this case the overlap integral of the electron wave functions takes a significant value. As a result, the conditions for the formation of quasi-molecules from quantum dots can be created.
We have shown that in such a nanoheterostructures acting as “exciton molecules” (biexcitons consisting of spatially separated electrons and holes) are the quantum dots of aluminum oxide with excitons localizing over their surfaces. The position of the biexciton state energy band depends both on the mean radius of the quantum dots, and the distance between their surfaces, which enables one to purposefully control it by varying these parameters of the nanostructure.
As our variational calculations show, the interaction of the excitons with the surfaces of quantum dots (“intramolecular” interaction) is much stronger than that between quantum dots (“intermolecular” interaction). Due to the translational symmetry of such a nanoheterostructures of quantum dots, it permits propagation of electronic excitation in the form of biexcitons.
As follows form the results of the variational calculations, the major contribution to the biexciton binding energy is from the energy of exchange interaction of electrons and holes, which by far surpasses that from their Coulomb interaction.
It is established that at constant concentrations of biexcitons at temperatures T below a certain critical temperature Tc due to the radiative annihilation of one of the excitons forming a biexciton one can expect a new spectral band of luminescence shifted relative to the exciton band by the biexciton binding energy . This new luminescence band disappears at temperatures above Tc. At a constant temperature Т < Tc the growth of exciton concentration brings about weakening of the exciton band and strengthening of the biexciton band of luminescence.
Alferov Zh. I. Nobel Lecture: The double heterostructure concept and its applications in physics, electronics, and technology. Rev. Modern Physics. 2001.73(3): 767. https://doi.org/10.1103/RevModPhys.73.767
Ekimov A., Hache F., Schanne-Klein M. Absorption and intensity-dependent photoluminescence measurements on CdSe quantum dots: assignment of the first electronic transitions: erratum. J. Opt. Soc. Amer., B. 1994. 11(3): 524. https://doi.org/10.1364/JOSAB.11.000524
Bondar N., Brodin M. Evolution of exciton states near the percolation threshold in two-phase systems with II-VI semiconductor quantum dots. Semiconductors. 2010. 44 (7): 884. https://doi.org/10.1134/S1063782610070109
Kulchin Yu. N., Shcherbakov A.V., Dzyuba V.P. Nonlinear-optical properties of heterogeneous liquid nanophase composites based on high-energy-gap Al2O3 nanoparticles. Quantum Electr. 2008. 38 (2): 154. https://doi.org/10.1070/QE2008v038n02ABEH013529
Dzyuba V.P., Krasnok A.E., Kulchin Yu.N. Nonlinear refractive index of dielectric nanocomposites in weak optical fields. Techn. Phys. Lett. 2010. 36 (11): 973. https://doi.org/10.1134/S1063785010110015
Pokutnyi S.I. Excition states in semiconductor quantum dots in the modified effective mass approximation. Semiconductors. 2007. 41 (11): 1323. https://doi.org/10.1134/S1063782607110097
Pokutnyi S.I. On an exciton with a spatially separated electron and hole in quasi-zero-dimensional semiconductor nanosystems. Semiconductors. 2013. 47 (6): 791. https://doi.org/10.1134/S1063782613060225
Pokutnyi S.I. Binding energy of the exciton of a spatially separated electron and hole in quasi-zero-dimensional semiconductor nanosystems. Technical Physics Letters. 2013. 39(3): 233. https://doi.org/10.1134/S1063785013030139
Pokutnyi S.I., Kulchin Yu. N., Dzyuba V.P. Binding energy of excitons formed from spatially separated electrons and holes in insulating quantum dots. Semiconductors. 2015. 49(10): 1311. https://doi.org/10.1134/S1063782615100218
Pokutnyi S.I. Excitons based on spatially separated electrons and holes in Ge/Si heterostructures with germanium quantum dots. Low Temperature Physics. 2016. 42(12): 1151. https://doi.org/10.1063/1.4973506
Pokutnyi S.I. Optical absorption by colloid quantum dots CdSe in the dielectric matrix. Low Temperature Physics. 2017. 43(12): 1797. https://doi.org/10.1063/1.5012798
Pokutnyi S.I. Optical spectroscopy of excitons with spatially separated electrons and holes in nanosystems containing dielectric quantum dots. J. Nanophoton. 2018. 12(2): 026013. https://doi.org/10.1117/1.JNP.12.026013
Pokutnyi S.I. Exciton spectroscopy with spatially separated electron and hole in Ge/Si heterostructure with germanium quantum dots. Low Temperature Physics. 2018. 44(8): 819. https://doi.org/10.1063/1.5049165
Pokutnyi S.I. Exciton spectroscopy of spatially separated electrons and holes in the dielectric quantum dots. Crystals. 2018. 8(4): 148. https://doi.org/10.3390/cryst8040148
Pokutnyi S.I. Biexcitons formed from spatially separated electrons and holes in quasi-zero-dimensional semiconductor nanosystems. Semiconductors. 2013. 47(12): 1626. https://doi.org/10.1134/S1063782613120178
Pokutnyi S.I., Kulchin Yu. N., Dzyuba V.P. Biexciton in nanoheterostructures of dielectric quantum dots. J. Nanophoton. 2016. 10: 036008. https://doi.org/10.1117/1.JNP.10.036008
Pokutnyi S.I., Kulchin Yu. N. Special Section Guest Editorial: Optics, Spectroscopy and Nanophotonics of Quantum Dots. J. Nanophoton. 2016. 10(3): 033501. https://doi.org/10.1117/1.JNP.10.036008
Pokutnyi S.I. Biexciton in quantum dots of cadmium sulfide in a dielectric matrix. Technical Physics. 2016. 61(11): 1737. https://doi.org/10.1134/S1063784216110190
Pokutnyi S.I. Excitonic quasimolecules in nanosystems of semiconductor and dielectric quantum dots. Modern Chemistry Applications. 2016. 4(4): 188. https://doi.org/10.4172/2329-6798.1000188
Pokutnyi S.I. Excitonic quasimolecules in nanosystems of quantum dots. Optical Engineering. 2017. 56(9): 091603. https://doi.org/10.1117/1.OE.56.9.091603
Pokutnyi S.I. Biexciton in nanoheterostructures of germanium quantum dots. Optical Engineering. 2017. 56 (6): 067104. https://doi.org/10.1117/1.OE.56.6.067104
S.I. Pokutnyi. Excitonic quasimolecules formed by spatially separated electrons and holes in a Ge/Si heterostructure with germanium quantum dots. J. Appl. Spectroscopy. 2017. 84(2): 268. https://doi.org/10.1007/s10812-017-0462-y
Pokutnyi S.I., Kulchin Yu. N., Dzyuba V.P. Biexciton states in nanoheterostructures of dielectric quantum dots. J. Physics Conference Series. 2018. 1092 (1): 12029. https://doi.org/10.1088/1742-6596/1092/1/012029
Pokutnyi S.I. Exciton quasimolecules formed from spatially separated electrons and holes in nanostructures with quantum dots of germanium. Molecular Crystals and Liquid Crystals. 2018. 674(1): 92. https://doi.org/10.1080/15421406.2019.1578515
Yakimov A.I., Dvurechensky A.V. Effects of electron-electron interaction in the optical properties of dense arrays of quantum dots Ge/Si. JETP. 2001. 119: 574.
Grabovskis V., Dzenis Y., Ekimov A. Photoionization of semiconductor microcrystals in glass. Sov. Phys. Solid State. 1989. 31(1): 272.
Bondar N. Photoluminescence quantum and surface states of excitons in ZnSe and CdS nanoclusters. J. Luminescence. 2010. 130(1): 1. https://doi.org/10.1016/j.jlumin.2009.07.015
Ovchinnikov O.V., Smirnov M.S., Shatskikh T.S. Spectroscopic investigation of colloidal CdS quantum dots - methylene blue hybrid associates. J. Nanopart. Res. 2014. 16: 2286. https://doi.org/10.1007/s11051-014-2286-5
Dzyuba V.P., Kulchin Yu. N., Milichko V.A. Quantum size states of a particle inside the nanopheres. Advanced Material Research A, 2013. 677: 42. https://doi.org/10.4028/www.scientific.net/AMR.677.42
Lalumiure K., Sanders B., Van Loo F. Imput - output theory for waveguide QED with an ensemble of inhomogeneous atoms. Phys. Rev. A. 2013. 88: 43806. https://doi.org/10.1103/PhysRevA.88.043806
Van Loo F, Fedorov A, Lalumiure K. Photon-mediated interactions between distant artificial atoms. Science, 2013. 342: 1494. https://doi.org/10.1126/science.1244324
Lozovik Y.E. Electronic and collective properties of topological insulators. Advanc. Phys. Scienc. 2014. 57: 653.
Valiev K. Quantum computers and quantum computing. Advanc. Phys. Sc., 2005. 48: 1. https://doi.org/10.1070/PU2005v048n01ABEH002024
Pokutnyi S.I. Optical nanolaser on the heavy hole transition in semiconductor nanocrystals: Theory. Phys. Letter. A. 2005. 342 (4): 347. https://doi.org/10.1016/j.physleta.2005.04.070
Pokutnyi S.I. Stark effect in semiconductor quantum dots. J. Applied Physics. 2004. 96: 100015. https://doi.org/10.1063/1.1759791
Pokutnyi S.I., Ovchinnikov O.V., Smirnov M.S. Sensitization of photoprocesses in colloidal Ag2S quantum dots by dye molecules. J. Nanophoton. 2016. 10: 033505. https://doi.org/10.1117/1.JNP.10.033505
Pokutnyi S.I., Ovchinnikov O.V. Relationship between structural and optical properties in colloidal CdxZn1-xS quantum dots in gelatin. J. Nanophoton. 2016. 10: 033507. https://doi.org/10.1117/1.JNP.10.033507
Pokutnyi S.I., Ovchinnikov O.V. Absorption of light by colloidal semiconducor quantum dots. J. Nanophoton. 2016. 10: 033506. https://doi.org/10.1117/1.JNP.10.033506
Pokutnyi S.I. Strongly absorbing light nanostructures containing metal quantum dots. J. Nanophoton. 2018. 12 (1): 012506. https://doi.org/10.1117/1.JNP.12.012506
Pokutnyi S.I., Kulchin Yu.N., Amosov A.V., Dzyuba V.P. Optical absorption by a nanosystem with dielectric quantum dots. Proc. SPIE. 2019. 11024: 1102404.
Pokutnyi S.I. Exciton states formed by spatially separated electron and hole in semiconductor quantum dots. Technical Physics. 2015. 60: 1615. https://doi.org/10.1134/S1063784215110249
Pokutnyi S.I. Spectroscopy of quasiatomic nanostructures. J. Optical Technol. 2015. 82: 280. https://doi.org/10.1364/JOT.82.000280