Effective permittivity of co-evaporated metal-organic mixed films

Doping process is widely used to improving emission performance of MgO films thicker than 10 nm via assisting the surface recharge and changing in electron structure. The present paper briefly reviews this strategy in a search for the new materials and structures being effective for secondary electron emission (SEE) and their diagnostics. Then, Metal-Organic Chemical Vapor Deposition (MOCVD) coupled with the specially selected precursor is suggested here as a new technique that transforms the refractory oxides to nanoscale, defect-disordered materials able to solid-solid interaction at 450 °C. Primary experiments have been performed for demanded mixed films based on MgO with ZrO2 and CeO2 additions. A dopant impact on facilitating the formation of oxygen vacancies in the host oxide and on the features of new mixed phases have been studied by new diagnostic means, based primarily on chemical method of differential dissolution. The method brought out the effective solvents that were the probes for identifying the nanoscale and amorphous phases possessing by the different defects on the surface of MgO films and determining contents of these phases. This approach allowed us to explain the origin of mixed phases and to estimate contribution of each from them in the macroscopic SEE properties.

Download Full-text

Electron microscope characterization of MOCVD-grown gap layers on Si

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144991 ◽

1986 ◽

Vol 44 ◽

pp. 724-725

Author(s):

K.M. Jones ◽

M.M. Al-Jassim ◽

J.M. Olson

Keyword(s):

Atmospheric Pressure ◽

Vapour Deposition ◽

Chemical Vapour ◽

Organic Chemical ◽

Lattice Match ◽

Si Substrates ◽

Metal Organic ◽

Good Lattice ◽

Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Download Full-text

Structural and electronic properties of defects in semiconductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136398 ◽

1995 ◽

Vol 53 ◽

pp. 4-5

Author(s):

J.L. Batstone

Keyword(s):

Semiconductor Device ◽

Chemical Vapor ◽

Misfit Strain ◽

Organic Chemical ◽

Extended Defects ◽

Transmission Electron ◽

Semiconductor Thin Films ◽

Wide Range ◽

Metal Organic ◽

Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

Download Full-text

Metal-Organic Frameworks

10.1021/acs.infocus.7e4004 ◽

2021 ◽

Author(s):

Lars Öhrström ◽

Francoise M. Amombo Noa

Keyword(s):

Metal Organic Frameworks ◽

Metal Organic

Download Full-text

Substrate templated synthesis of single-phase and uniform Zr-porphyrin-based metal–organic frameworks

Inorganic Chemistry Frontiers ◽

10.1039/c9qi01045a ◽

2020 ◽

Vol 7 (1) ◽

pp. 221-231

Author(s):

Seong Won Hong ◽

Ju Won Paik ◽

Dongju Seo ◽

Jae-Min Oh ◽

Young Kyu Jeong ◽

...

Keyword(s):

Chemical Bath Deposition ◽

Single Phase ◽

Metal Organic Frameworks ◽

Templated Synthesis ◽

Pore Structures ◽

Phase Pure ◽

Metal Organic ◽

Cbd Method

We successfully demonstrate that the chemical bath deposition (CBD) method is a versatile method for synthesizing phase-pure and uniform MOFs by controlling their nucleation stages and pore structures.

Download Full-text

Multifunctional metal–organic framework heterostructures for enhanced cancer therapy

Chemical Society Reviews ◽

10.1039/d0cs00178c ◽

2021 ◽

Author(s):

Jintong Liu ◽

Jing Huang ◽

Lei Zhang ◽

Jianping Lei

Keyword(s):

Cancer Therapy ◽

General Principle ◽

Biomedical Applications ◽

Metal Organic Framework ◽

Metal Organic ◽

Functional Modulation ◽

Organic Framework

We review the general principle of the design and functional modulation of nanoscaled MOF heterostructures, and biomedical applications in enhanced therapy.

Download Full-text