Wyniki wyszukiwania - Biblioteka Nauki

Ten serwis zostanie wyłączony 2025-02-11.

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

4 Acta Physica Polonica A

4 1997

Znaleziono wyników: 4

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Exciton States in Type-II ZnSe/BeTe Quantum Wells

100%

Platonov A. V. , Yakovlev D. R. , Zehnder U. , Kochereshko V. P. , Ossau W. , Fischer F. , Litz T. , Waag A. , Landwehr G.

nr 5

953-957

We present an optical investigation of novel heterostructures based on beryllium chalcogenides with a type-I and type-II band alignment. In the type-II quantum well structures (ZnSe/BeTe) we observed a strong exciton transition involving an electron confined in the conduction band well and a hole localized in the valence band barrier (both in ZnSe layer). This transition is drastically broadened by the temperature increase due to enhanced exciton-acoustic phonon interaction.

Investigation of Spin-Glass Transition in Semimagnetic Quantum Wells Based on Cd_{1-x}Mn_{x}Te by Means of Optical Spectroscopy

100%

Zehnder U. , Yakovlev D. R. , Ossau W. , Waag A. , Landwehr G. , Wojtowicz T. , Karczewski G. , Kossut J.

nr 5

1075-1078

The spin-glass transition in Cd_{1-x}Mn_{x}Te epitaxial layers and bulk samples with 0.24 ≤ x ≤ 0.43 and in quantum well structures on the basis of Cd_{1-x}Mn_{x}Te were investigated by means of optical spectroscopy. Reduction of dimensionality of Cd_{1-x}Mn_{x}Te layers down to the quasi-two-dimensional case realized in Cd_{1-x}Mn_{x}Te/Cd_{1- y}Mn_{y}Te heterostructures frustrates the spin-glass formation, which is in agreement with theoretical predictions. The spin-glass formation is also frustrated in the vicinity of interfaces between semimagnetic and nonmagnetic semiconductors in CdTe/Cd_{1-x}Mn_{x}Te quantum wells.

Novel CdTe/CdMgTe Graded Quantum Well Structures

100%

Wojtowicz T. , Kutrowski M. , Karczewski G. , Cywiński G. , Surma M. , Kossut J. , Yakovlev D. R. , Ossau W. , Landwehr G. , Kochereshko V.

nr 5

1063-1066

We report on growth and magnetooptical studies of two types of novel CdTe/CdMgTe quantum well structures having a precisely controlled grading of either the quantum well width or the donor concentration in a direction perpendicular to the growth axis. The presence of two-dimensional electron gas of varying concentration produced by the graded modulation doping was evidenced by observation of negatively charged exciton-electron complexes (X¯).

Half-Parabolic Quantum Wells of Diluted Magnetic Semiconductor Cd_{1-x}Mn_{x}Te

80%

Kutrowski M. , Wojtowicz T. , Cywiński G. , Karczewski G. , Janik E. , Dynowska E. , Kossut J. , Kossacki P. , Fiederling R. , Pfeuffer-Jeschke A. , Ossau W.

nr 5

887-890

We report on magnetooptical studies of MBE-grown half-parabolic CdTe/Cd_{x}Mn_{1-x}Te quantum well structures. The value of the valence band offset Q_{v}=0.4 ± 0.05 was determined by comparing energies of optical transitions in the absence of a magnetic field with model calculations. This value was verified by fitting the observed spin splitting of the lowest heavy hole (hh) state. We discuss also the temperature dependence of Q_{v}.