Optical properties of electron-irradiated GaN

The electronic structure of defects produced by 2.5-MeV electron irradiation and their effect on optical properties of GaN are investigated using photoluminescence (PL) and optically detected magnetic resonance (ODMR) techniques. The electron irradiation is shown to produce, in particular, a deep PL band with a no-phonon line at around 0.88 eV followed by a phonon-assisted sideband. We suggest that this emission is caused by an internal transition between excited and ground state of a deep defect. The excited state is a multiple-level state, as revealed from temperature dependent PL and level anti-crossing experiments. The electronic structure of the 0.88 eV defect is shown to be sensitive to the internal strain in the GaN epilayers. The ODMR studies reveal that the principal axis of the defect coincides with the c-axis of the host lattice and should therefore be either an on-site point defect or an axial complex defect along the c-axis.

Download Full-text

Effect of temperature on Raman intensity of nm-thick WS2: combined effects of resonance Raman, optical properties, and interface optical interference

Nanoscale ◽

10.1039/c9nr10186a ◽

2020 ◽

Vol 12 (10) ◽

pp. 6064-6078 ◽

Cited By ~ 2

Author(s):

Hamidreza Zobeiri ◽

Shen Xu ◽

Yanan Yue ◽

Qianying Zhang ◽

Yangsu Xie ◽

...

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

2D Materials ◽

Resonance Raman ◽

Effect Of Temperature ◽

Combined Effects ◽

Raman Intensity ◽

Temperature Dependent ◽

Optical Interference ◽

Rich Information

Temperature dependent Raman intensity of 2D materials features very rich information about the material's electronic structure, optical properties, and nm-level interface spacing.

Download Full-text

Impact of excess PbI2 on the structure and the temperature dependent optical properties of methylammonium lead iodide perovskites

Journal of Materials Chemistry C ◽

10.1039/c8tc02237b ◽

2018 ◽

Vol 6 (28) ◽

pp. 7512-7519 ◽

Cited By ~ 25

Author(s):

Tobias Meier ◽

Tanaji P. Gujar ◽

Andreas Schönleber ◽

Selina Olthof ◽

Klaus Meerholz ◽

...

Keyword(s):

Thin Films ◽

Phase Transition ◽

Optical Properties ◽

Electronic Structure ◽

Binding Energy ◽

Direct Impact ◽

Lead Iodide ◽

Temperature Dependent ◽

Methylammonium Lead Iodide ◽

Transition Behaviour

Excess PbI2 in MAPbI3 thin films has no direct impact on the electronic structure but changes the temperature dependence of the exciton binding energy and the phase transition behaviour.

Download Full-text

Structural/Property Relationships for Optical Materials

MRS Proceedings ◽

10.1557/proc-329-215 ◽

1993 ◽

Vol 329 ◽

Author(s):

Vivien D.

Keyword(s):

Crystal Structure ◽

Optical Properties ◽

Electronic Structure ◽

Chemical Composition ◽

Field Strength ◽

Optical Materials ◽

Site Occupancy ◽

Laser Materials ◽

Crystal Field Strength ◽

The Matrix

AbstractIn this paper the relationships between the crystal structure, chemical composition and electronic structure of laser materials, and their optical properties are discussed. A brief description is given of the different laser activators and of the influence of the matrix on laser characteristics in terms of crystal field strength, symmetry, covalency and phonon frequencies. The last part of the paper lays emphasis on the means to optimize the matrix-activator properties such as control of the oxidation state and site occupancy of the activator and influence of its concentration.

Download Full-text

Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles

MRS Proceedings ◽

10.1557/proc-536-257 ◽

1998 ◽

Vol 536 ◽

Author(s):

H. Porteanu ◽

A. Glozman ◽

E. Lifshitz ◽

A. Eychmüller ◽

H. Weller

Keyword(s):

Optical Properties ◽

Magnetic Resonance ◽

Cds Nanoparticles ◽

Electron Hole ◽

Cladding Layer ◽

Double Beam ◽

Optically Detected Magnetic Resonance ◽

Optically Detected ◽

Cladding Layers ◽

Hole Recombination

AbstractCdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.

Download Full-text

Controlling the non-linear optical properties of MgO by tailoring the electronic structure

Applied Physics B ◽

10.1007/s00340-020-7393-7 ◽

2020 ◽

Vol 126 (3) ◽

Author(s):

Mukhtar Hussain ◽

Hugo Pires ◽

Willem Boutu ◽

Dominik Franz ◽

Rana Nicolas ◽

...

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

Non Linear ◽

Linear Optical Properties ◽

Linear Optical

Download Full-text

Temperature‐dependent Formation of Ozone in Solid Oxygen by 5 keV Electron Irradiation and Implications for Solar System Ices

The Astrophysical Journal ◽

10.1086/521216 ◽

2007 ◽

Vol 669 (2) ◽

pp. 1414-1421 ◽

Cited By ~ 23

Author(s):

Bhalamurugan Sivaraman ◽

Corey S. Jamieson ◽

Nigel J. Mason ◽

Ralf I. Kaiser

Keyword(s):

Solar System ◽

Electron Irradiation ◽

Temperature Dependent ◽

Solid Oxygen

Download Full-text

DFT Study of Electronic Structure and Optical Properties of Kaolinite, Muscovite, and Montmorillonite

Crystals ◽

10.3390/cryst11060618 ◽

2021 ◽

Vol 11 (6) ◽

pp. 618

Author(s):

Layla Shafei ◽

Puja Adhikari ◽

Wai-Yim Ching

Keyword(s):

Mechanical Properties ◽

Optical Properties ◽

Electronic Structure ◽

Hydrogen Bonds ◽

Clay Minerals ◽

Clay Mineral ◽

Bond Order ◽

Deep Understanding ◽

Pharmaceutical Applications ◽

Structure Properties

Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

Download Full-text