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Microstructural study of MBE-grown ZnO film on GaN/sapphire (0001) substrate

100%

Li H., Sang J., Liu C., Lu H., Cao J.

Open Physics

2008

vol. 6

issue 3

638-642

Single crystalline ZnO film is grown on GaN/sapphire (0001) substrate by molecular beam epitaxy. Ga2O3 is introduced into the ZnO/GaN heterostructure intentionally by oxygen-plasma pre-exposure on the GaN surface prior to ZnO growth. The crystalline orientation and interfacial microstructure are characterized by X-ray diffraction and transmission electron microscopy. X-ray diffraction analysis shows strong c-axis preferred orientation of the ZnO film. Cross-sectional transmission electron microscope images reveal that an additional phase is formed at the interface of ZnO/GaN. Through a comparison of diffraction patterns, we confirm that the interface layer is monoclinic Ga2O3 and the main epitaxial relationship should be $$ (0001)_{ZnO} \parallel (001)_{Ga_2 O_3 } \parallel (0001)_{GaN} $$ and $$ [2 - 1 - 10]_{ZnO} \parallel [010]_{Ga_2 O_3 } \parallel [2 - 1 - 10]_{GaN} $$.

Optimizing the InGaAs/GaAs Quantum Dots for 1.3 μm Emission

84%

Maryński A., Mrowiński P., Ryczko K., Podemski P., Gawarecki K., Musiał A., Misiewicz J., Quandt D., Strittmatter A., Rodt S., Reitzenstein S., Sęk G.

Acta Physica Polonica A

2017

vol. 132

issue 2

386-390

Hereby we present comprehensive experimental and theoretical study on fundamental optical properties and electronic structure of GaAs-based quantum dots grown using metalorganic chemical vapor deposition technique. The substantial redshift of emission, to the second telecommunication window of 1.3 μm, in comparison to standard InGaAs/GaAs quantum dots is obtained via strain engineering utilizing additional capping layer of In_{0.2}Ga_{0.8}As in this context referred to as strain reducing layer. It ensures lowering of the energy of the ground state transition to more application relevant spectral range. Optical properties of the quantum dot structure has been experimentally characterized by means of photoreflectance spectroscopy and power-dependent photoluminescence revealing 3 transitions originating from hybrid states confined in an asymmetric double quantum well formed of the wetting layer and strain reducing layer, as well as higher states of the quantum dots themselves with the first excited state transition separated by 67 meV from the ground state transition. Origin of the observed transitions was confirmed in theoretical modelling using 1-band single-particle approach for the quantum well part, and excitonic quantum dot spectrum obtained within 8 band k·p formalism followed by configuration interaction calculations, respectively. Additionally, photoluminescence excitation spectroscopy measurements allowed to identify a spectral range for efficient quasi-resonant excitation of the investigated quantum dots into the 2D density of states to be in the range of 835-905 nm.

Calculations of Dark Current in Interband Cascade Type-II Infrared InAs/GaSb Superlattice Detector

84%

Hackiewicz K., Martyniuk P., Rutkowski J., Kowalewski A.

Acta Physica Polonica A

2017

vol. 132

issue 4

1415-1419

In this paper we investigate interband cascade type-II mid-wavelength infrared InAs/GaSb superlattice detector in temperature range from 200 K to 300 K. The paper is based on the theoretical calculation of dark current treated as a sum of two components: average bulk current and average leakage current, flowing through the device. The average leakage current results from a comparison of theoretically calculated bulk current and measured one. We show that it is possible to fit theoretical model to experimental data, assuming that transport in absorber is determined by the dynamics of the intrinsic carriers. Based on the fit we estimated carrier lifetime greater than 100 ns in temperature range 200-300 K.

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2 Acta Physica Polonica A

1 Open Physics

2 2017

1 2008

1 Cao J.

1 Gawarecki K.

1 Hackiewicz K.

1 Kowalewski A.

1 Li H.

1 Liu C.

1 Lu H.

1 Martyniuk P.

1 Maryński A.

1 Misiewicz J.

1 Mrowiński P.

1 Musiał A.

1 Podemski P.

1 Quandt D.

1 Reitzenstein S.

1 Rodt S.

1 Rutkowski J.

1 Ryczko K.

1 Sang J.

1 Strittmatter A.

1 Sęk G.

Search results

Microstructural study of MBE-grown ZnO film on GaN/sapphire (0001) substrate

Optimizing the InGaAs/GaAs Quantum Dots for 1.3 μm Emission

Calculations of Dark Current in Interband Cascade Type-II Infrared InAs/GaSb Superlattice Detector