Polarization of Germanium Quantum Dots in Heterostructure Ge/Si …
625
A mechanism is proposed for the onset of the dipole moments of electron transitions in a nanosystem containing germanium QDs with average radii a not exceeding
25 nm, grown in a silicon matrix studied under experimental conditions [1–3].
The mechanism of QD polarizability photoexcitation described above does not
take into account the exciton–phonon interaction, which mainly leads to a broadening
of the kinetic energy spectrum and a decrease in the lifetime of the exciton. But this
broadening will be small due to the small lifetime of the exciton, and the thermal
equilibrium with the surrounding atoms does not take place. It is shown that electron
transitions from SIE levels (n = 1, l) to higher excited exciton levels (n = 1, l + 1)
belonging to the surface exciton zone, which was located in the bandgap of the silicon
matrix, as well as in the conduction band of the silicon matrix [5] caused the dipole
moments of the transitions D
1,l+1
1,l (a) (26), the values of which are proportional to
the radii a of QDs and exceeded the values typical for semiconductors by two orders
[33]. The resonance optical absorption of the nanosystem in the infrared region of
the spectrum (from 80 meV to 248 meV) can apparently be observed experimentally
at room temperature.
Using the present model of a Ge/Si heterostructure with germanium QDs, it was
shown [5] that interband and interband transitions between SIE states caused significant radiation in the infrared region of wavelengths in the energy range (≤330 meV).
This energy range (≤330 meV) was contained in the spectral region (0.20–1.14)
eV, which was observed in experiments [1–3]. Therefore, the present model of
the Ge/Si heterostructure with germanium QDs partially explains the experimental
results [1–3].
References
1. Yakimov AI, Dvurechensky AV, Nikiforov AI (2001) JETP Lett 73:529
2. Yakimov AI, Dvurechensky AV, Nikiforov AI (2001) JETP 119:574
3. Smagina JV, Dvurechenskiy AV, Seleznev VA (2015) Semiconductors 49:749
4. Pokutnyi SI (2016) Low Temp Phys 42:1151
5. Pokutnyi SI (2018) Low Temp Phys 44:819
6. Alferov ZhI (2002) Nobel lecture. Usp Fiz Nauk 172:1068
7. Pokutnyi SI (2013) Semiconductors 47:791
8. Pokutnyi SI, Culchin YuN, Dzyuba VP (2015) Semiconductors 49:1311
9. Pokutnyi SI (2013) Technical Phys Lett 39:233
10. Pokutnyi SI (2015) Technical Phys 60:1615
11. Pokutnyi SI (2007) Semiconductors 41:1323
12. Pokutnyi SI (2010) Semiconductors 44:507–514
13. Chang WH, Chou AT, Chen WY (2003) Appl Phys Lett 83:2958
14. Elcurdi M, Boucaud P, Sauvage S (2003) Physica E 16:523
15. Elfving A, Hansson GV, Ni WX (2003) Physica E 16:528
16. Dvurechensky AV, Yakimov AI, Kirienko VV (2018) Defect Diffuss. Forum. 386:68
17. Pakhanov N, Pchelyakov OP, Yakimov AI (2017) Optoelectron Instrum Data Process 53:190
18. Achtstein AW, Prudnikau AV, Ermolenko MV, Gurinovich LI, Gaponenko SV (2014) ACS
Nano 8:7678
19. Gaponenko SV, Demir HV, Seassal C (2016) Optics Express 24(A):430
625
A mechanism is proposed for the onset of the dipole moments of electron transitions in a nanosystem containing germanium QDs with average radii a not exceeding
25 nm, grown in a silicon matrix studied under experimental conditions [1–3].
The mechanism of QD polarizability photoexcitation described above does not
take into account the exciton–phonon interaction, which mainly leads to a broadening
of the kinetic energy spectrum and a decrease in the lifetime of the exciton. But this
broadening will be small due to the small lifetime of the exciton, and the thermal
equilibrium with the surrounding atoms does not take place. It is shown that electron
transitions from SIE levels (n = 1, l) to higher excited exciton levels (n = 1, l + 1)
belonging to the surface exciton zone, which was located in the bandgap of the silicon
matrix, as well as in the conduction band of the silicon matrix [5] caused the dipole
moments of the transitions D
1,l+1
1,l (a) (26), the values of which are proportional to
the radii a of QDs and exceeded the values typical for semiconductors by two orders
[33]. The resonance optical absorption of the nanosystem in the infrared region of
the spectrum (from 80 meV to 248 meV) can apparently be observed experimentally
at room temperature.
Using the present model of a Ge/Si heterostructure with germanium QDs, it was
shown [5] that interband and interband transitions between SIE states caused significant radiation in the infrared region of wavelengths in the energy range (≤330 meV).
This energy range (≤330 meV) was contained in the spectral region (0.20–1.14)
eV, which was observed in experiments [1–3]. Therefore, the present model of
the Ge/Si heterostructure with germanium QDs partially explains the experimental
results [1–3].
References
1. Yakimov AI, Dvurechensky AV, Nikiforov AI (2001) JETP Lett 73:529
2. Yakimov AI, Dvurechensky AV, Nikiforov AI (2001) JETP 119:574
3. Smagina JV, Dvurechenskiy AV, Seleznev VA (2015) Semiconductors 49:749
4. Pokutnyi SI (2016) Low Temp Phys 42:1151
5. Pokutnyi SI (2018) Low Temp Phys 44:819
6. Alferov ZhI (2002) Nobel lecture. Usp Fiz Nauk 172:1068
7. Pokutnyi SI (2013) Semiconductors 47:791
8. Pokutnyi SI, Culchin YuN, Dzyuba VP (2015) Semiconductors 49:1311
9. Pokutnyi SI (2013) Technical Phys Lett 39:233
10. Pokutnyi SI (2015) Technical Phys 60:1615
11. Pokutnyi SI (2007) Semiconductors 41:1323
12. Pokutnyi SI (2010) Semiconductors 44:507–514
13. Chang WH, Chou AT, Chen WY (2003) Appl Phys Lett 83:2958
14. Elcurdi M, Boucaud P, Sauvage S (2003) Physica E 16:523
15. Elfving A, Hansson GV, Ni WX (2003) Physica E 16:528
16. Dvurechensky AV, Yakimov AI, Kirienko VV (2018) Defect Diffuss. Forum. 386:68
17. Pakhanov N, Pchelyakov OP, Yakimov AI (2017) Optoelectron Instrum Data Process 53:190
18. Achtstein AW, Prudnikau AV, Ermolenko MV, Gurinovich LI, Gaponenko SV (2014) ACS
Nano 8:7678
19. Gaponenko SV, Demir HV, Seassal C (2016) Optics Express 24(A):430