Zoltán Lábadi

High power InP/InGaAsP buried heterostructure laser for a wavelength of 1.15 μm

Abstract InP/InGaAsP buried heterostructure lasers for a wavelength of 1.15 μm with optimized parameters can play an important role as pump sources for blue-upwards conversion fiber lasers. This paper reports the single-step liquid phase epitaxial growth and characterization of a double-channelled substrate InP/InGaAsP buried heterostructure laser diode for a wavelength of 1.15 μm. Optimum conditions for separate growth of an InGaAsP buried active layer on the double-channelled InP substrate have been obtained. Output powers over 100 mW have been obtained by determining the appropriate cavity length and the reflectivity of the mirror facets. High power single-transverse mode operation and a nearly symmetrical beam of the lasers are advantageous for pumping of fiber lasers.

ZnO layers deposited by Atomic Layer Deposition

The structure of 40 nm thick epitaxial ZnO layers grown on single crystalline sapphire and GaN substrates by atomic layer deposition has been studied using transmission electron microscopy. The growth is carried out between 150?C and 300?C without any buffer layer using di-ethyl zinc and water precursors. The ZnO layer on sapphire is found to be polycrystalline, which is probably due to the large misfit (~15 %) and the relatively low deposition temperature. However, the small misfit (~1.8 %) between the ZnO layer that is deposited on GaN at 300?C resulted in a high quality single crystalline layer.

The Low‐frequency Noise in Al Doped ZnO Films

The electric noise of Al doped ZnO layers were measured. The optically transparent layers were prepared by reactive sputtering. In the low frequency range pure 1/f noise was observed. Extremely large Hooge parameters were obtained.

Selective liquid-phase epitaxy growth of InxGa1−xAsyP1−y on structured GaAs(100) substrates

Abstract This work deals with the liquid-phase epitaxy (LPE) growth of In x Ga 1−x As y P 1−y materials lattice matched to GaAs. We examine the growth of two different In x Ga 1−x As y P 1−y compositions denoted A and B. They have 1.9 eV and 1.58 eV band gap energies respectively. We estimate the optical two-phase LPE growth conditions for such quaternaries and for multiple submicron layers of A-B Materials. We report the dependence of the growth kinetics on the crystal facets. We have found that the LPE growth of ultrathin multilayers in the In x Ga 1−x As y P 1−y / GaAs system, with uniform layer thickness and without noticeable transition layers was possible. Furthermore, we have found anisotropic effects on non-planar substrates (i.e. faster kinetics in the (100) direction than in the (111) direction). These results can be utilized to grow, by LPE, visible lasers containing a multiple-quantum-well active region and buried structures.