The influence of the early stage of ZnSe growth on GaAs(001) on the defect-related luminescence

Abstract

We have grown ZnSe layers by molecular beam epitaxy (MBE) on GaAs substrates which were deoxidized by atomic hydrogen at different temperatures. The surface roughness of the GaAs substrate was measured by atomic force microscopy (AFM); that of the growing ZnSe layers was determined from AFM measurement and the full width at half maximum of the reflection high-energy electron diffraction (RHEED) reflexes during the nucleation process and the layer growth. We find a strong influence of the substrate temperature during the deoxidization process on the surface roughness and the density of extended defects in the ZnSe layers. The density of extended defects was measured using high-resolution x-ray diffraction and spatially resolved cathodoluminescence (CL) images which were obtained at the defect-related Y 0 emission at about 474 nm. We find that the intensity ratio of the defect-related Y 0 emission and the near band edge excitonic emission is proportional to D 2.9 where D is the density of extended defects in the layer. We explain this relation by a model calculation which assumes radiative and non-radiative recombination of bound excitons as well as radiative recombination of electron-hole pairs via recombination centres which are involved in the Y 0 transition.

Sublimation sandwich route to ultralong zinc-blende ZnSe nanowires and the cathodoluminescence properties of individual nanowires

“…V Zn act as the acceptor species while Zn i as the donor species. In the case, all carriers excited to the conduction band almost instantaneously decay to shallow donor levels and recombine with acceptor states emitting photons corresponding to donor-acceptor pair recombination mechanism, which finally results in the broad, strong green-red emission band of the ZnSe nanowires [30][31][32][33]. Fig.…”

Optimization of the Growth of the Van der Waals Materials Bi2Se3 and (Bi0.5In0.5)2Se3 by Molecular Beam Epitaxy

“…Apart from the valence electron difference, selenium and arsenic are next to each other in the periodic table, so they have similar atomic masses and chemical reactivities. Selenium passivation of GaAs (001) has already been investigated at length in the growth of chalcogenide semiconductors like ZnSe. − However, different surface reconstructions, including 4 × 3, 2 × 3, and 2 × 1, have been observed in RHEED when the substrate is exposed to selenium flux at different substrate temperatures . For selenium exposure at high substrate temperatures (>200 °C), the most reported reconstruction in both experiments and theoretical calculations is 2 × 1. − In this configuration, the first layer of arsenic is completely substituted by selenium, which is connected to two gallium atoms in the second layer; the third layer is mostly replaced (>90%) by selenium, while the fifth layer is partially replaced .…”

Growth of ZnSe(1−x)Tex epilayers by isothermal closed space sublimation

“…[1][2][3][4][5] It is well known that even low tellurium concentrations in ZnSe have a positive effect on hardness, 6 density of dislocations, 7 p-doping, [8][9][10] and contacting. Potential applications of II-VI semiconductor compounds in blue-green emitting optoelectronic devices have driven extensive and successful efforts to grow high quality ZnSe layers on GaAs substrates by different growth techniques.…”