Home  About us  Contact
 

InGaN/GaN Quantum Wells (ingan/gan + quantum_well)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Nonradiative resonance energy transfer directed from colloidal CdSe/ZnS quantum dots to epitaxial InGaN/GaN quantum wells for solar cells

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010
Sedat Nizamoglu
Abstract We report on Förster-type nonradiative resonance energy transfer (NRET) directed from colloidal quantum dots (QDs) to epitaxial quantum wells (QWs) with an efficiency of 69.6% at a rate of 1.527 ns,1 for potential application in III-nitride based photovoltaics. This hybrid exciton generation,collection system consists of chemically-synthesized cyan CdSe/ZnS core/shell QDs (,PL = 490 nm) intimately integrated on epitaxially-grown green InGaN/GaN QWs (,PL = 512 nm). To demonstrate directional NRET from donor QDs to acceptor QWs, we simultaneously show the decreased photoluminescence decay lifetime of dots and increased lifetime of wells in the hybrid dipole,dipole coupled system. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Quantitative evaluation of the atomic structure of defects and composition fluctuations at the nanometer scale inside InGaN/GaN heterostructures

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 12 2004
P. Ruterana
Abstract Investigation is carried out by high-resolution electron microscopy on threading dislocations using data treatments with procedures that allow the extraction of the most likely atomic configurations. We also report In composition fluctuations inside InGaN/GaN quantum wells by coupling HRTEM, image simulation and Finite Element Modelling (FEM) of the thin foil relaxation. The results show that the indium content may be close to x = 1.0 in the clusters and this is much higher that was previously suggested by 2D FEM modelling. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Theoretical investigations on anisotropic optical properties in semipolar and nonpolar InGaN quantum wells

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2008
Kazunobu Kojima
Abstract The anisotropic band structures and spontaneous emission of the non c plane InGaN/GaN quantum wells (QWs) were computed based on the k·p perturbation theory. Spontaneous emission due to the A valence band is strongly polarized perpendicular to the c axis, while that from the B band has 90º-rotated polarization, for the crystal angle , larger than 50°. However, it was found that excited carriers can distribute into both the A and B bands, so that the effective polarization Peff defined by the integrated luminescence intensity is much reduced even for nonpolar InGaN/GaN QWs. Thus, Peff was systematically studied for arbitrary planes. We found that the energy separation between the A and B bands becomes significant and carrier population of the B valence band is suppressed as the In content increases, when Peff approaches unity. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Fabrication and optical properties of nano-structured semipolar InGaN/GaN quantum wells on c-plane GaN template

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
Hongbo Yu
Abstract High density self-assembled nanostructured semipolar (NSSP) GaN pyramids are fabricated based on c-plane GaN template by in situ silane treatment followed by high temperature treatment. Semipolar InGaN/GaN multiple quantum wells (MQWs) were subsequently grown on the NSSP GaN. Optical properties of the MQWs were studied by temperature- dependent and excitation density varied photoluminescence. It was found that the internal electric field in the NSSP MQWs were remarkably reduced in comparison with planar c-plane MQWs. The internal quantum efficiency of the NSSP MQWs was measured to be > 30% which showed potential applications in III-nitride light emitters. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Optical properties of InGaN/GaN quantum wells on sapphire and bulk GaN substrate

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006
M. Dworzak
Abstract We investigated the recombination dynamics in InGaN quantum well (QW) structures, grown by metal organic chemical vapour deposition on sapphire and bulk GaN crystals. We present the results of time-integrated and time-resolved photoluminescence (PL) spectroscopy performed on single QWs with widths of 4.5 nm and 9.5 nm. The recombination mechanisms were studied at 5 K and elevated temperatures up to room temperature. Radiative and nonradiative life-times were determined. The luminescence properties are strongly influenced by the localization of excitons in a complex potential landscape with localization sites of varying depth. Redistribution of charges from shallow to deeper localization sites were observed. The band profile fluctuations influence the thermal stability of the luminescence. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Size and shape of In rich clusters and InGaN QWs at the nanometer scale

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005
P. Ruterana
Abstract Following the need to accurately understand the In composition fluctuations and their role on the optical properties of the GaN based heterostructures, an investigation of MOCVD InGaN/GaN quantum wells is carried out. To this end, quantitative High Resolution Transmission Electron Microscopy (HRTEM) is coupled with image simulation and Finite Element Method (FEM) for the thin foil relaxation modelling. The results show that the indium content can reach x = 1 in the clusters inside the core. In these MOCVD QWs, we attempt to connect the Quantum dot density, composition, and shape to the growth conditions, in order to help the engineering process of highly efficient devices. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Characteristics of amplified spontaneous emission of high indium content InGaN/GaN quantum wells with various silicon doping conditions

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
Yung-Chen Cheng
Abstract We compared the temperature dependent spectral variations of the amplified spontaneous emission (ASE) between InGaN/GaN quantum well samples of no doping, well doping, and barrier doping of silicon. The comparisons were particularly made between two series of samples with a low and a high indium content. The results show that a multi-peak ASE spectral feature and a low energy stimulated emission peak, existing at the photoluminescence shoulder, could be observed only in the high-indium-content, barrier-doped sample. Such results are supposed to originate from the formation of quantum dots of various sizes, concentrations, and shapes under the condition of barrier doping in the sample. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]