- Tytuł:
- Calorimetric Absorption Spectroscopy of Deep Defects and Quantum Dots
- Autorzy:
-
Heitz, R.
Podlowski, L.
Böhrer, J.
Hoffmann, A.
Broser, I.
Bimberg, D. - Powiązania:
- https://bibliotekanauki.pl/articles/1933692.pdf
- Data publikacji:
- 1995-10
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
71.55.Eq
73.20.Dx
71.70.Gm - Opis:
- In recent years calorimetric absorption spectroscopy has been developed to a powerful tool of semiconductor spectroscopy based on the detection of nonradiative relaxation processes. Calorimetric absorption spectroscopy is an ultrasensitive quantitative absorption technique. Recent investigations of Fe in III-V semiconductors and of InAs/GaAs quantum dots are presented here to illustrate the potential of the method. Sharp absorption lines are observed at the low energy onset of the Fe $\text{}^{3+}\text{}^{/}\text{}^{2+}$ charge transfer band in III-V semiconductors. Calorimetric absorption spectroscopy measurements in the mK range reveal a strong temperature dependence of their absorption strength identifying unambiguously Fe$\text{}^{3+}$($\text{}^{6}$A$\text{}_{1}$(S)) as a ground state. The excited state is attributed to (Fe$\text{}^{2+}$,h). The importance of exchange interaction for the observed fine structure is pointed out and binding energies are determined. The quantum yield of the intracenter $\text{}^{5}$Τ$\text{}_{2}$-$\text{}^{5}$E transition of F$\text{}^{2+}$ is determined to be below 50% at 2 K. A correlation between the nonradiative relaxation rate and the isotope splitting of the $\text{}^{5}$Τ$\text{}_{2}$-$\text{}^{5}$E transition is observed, demonstrating the crucial role of the dynamical Jahn-Teller coupling of the $\text{}^{5}$Τ$\text{}_{2}$ state to local Τ$\text{}_{2}$ modes for the multiphonon relaxation process. Quantum dots having a d-function density of states should exhibit no Stokes shift between absorption and emission as observed for one- and two-dimensional systems. Calorimetric absorption spectroscopy demonstrates ground state absorption coinciding in energy with the luminescence for self- organized InAs/GaAs quantum dot structures grown by MBE. Transitions into excited hole states are resolved and a comparison to photoluminescence excitation spectroscopy is presented.
- Źródło:
-
Acta Physica Polonica A; 1995, 88, 4; 619-630
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł