0000000000273716
AUTHOR
Said Hassani
A new approach to the growth of ZnO by vapour transport
The crystal growth of ZnO by vapour transport is classically made in presence of additional species which enhance the growth process. Usually, additional species have been considered as chemical transport agents that promote a typical CVT (Chemical Vapour Transport) process. Recently, we have proposed a new interpretation of the chemical role of some of these species. This new interpretation considers that, in some cases, the additional species promote a partial consumption of the O2 provided by the ZnO decomposition and, consequently, a Zn excess is generated. This excess of Zn pressure activates the ZnO decomposition and the growth rate is enhanced. Among those species, carbon shows an ad…
Study of the ZnO crystal growth by vapour transport methods
Abstract The crystal growth of ZnO by vapour transport is classically made with the assistance of additional species that produce a gaseous mixture, the role of which remains often uncertain in the transport and growth process. Initially, in order to study the mass transport process, a numerical simulation is made to analyse which are the requirements to have an effective transport. As the pressure of each gaseous species is generally unknown, the numerical study has been performed for different total pressures. It is found that, if congruent and equilibrium conditions are assumed at the sublimation and crystallisation interfaces, effective growth conditions can only be attained for a narro…
Effect of Growth Temperature on the Structural and Morphological Properties of MgCdO Thin Films Grown by Metal Organic Chemical Vapor Deposition
II-VI oxides ternary alloys have attracted considerable interest of the scientific community due to the possibility of modulating their interesting optoelectronic properties. Despite this interest, MgCdO has been poorly studied. In this work, by using the metal organic chemical vapor deposition method at low pressure, we have analyzed the synthesis of thin films of this alloy. Thus, for a fixed metal-organic precursors content, a change from Mg1-xCdxO (Mg-rich phase) to Cd1-xMgxO (Cd-rich phase) has been induced when decreasing the growth temperature. The temperature range where both phases coexist has been particularly analyzed. Using X-ray diffraction analysis and scanning electron micros…
The Scope of Zinc Oxide Bulk Growth
The techniques classically used for the growth of bulk ZnO crystals, melt-growth, vapour growth, solution-growth and hydrothermal growth, are reviewed. In the case of vapor growth, numerical simulations suggest that such species as H2 + H2O, CH4, Zn, C or Fe could act as sublimation activators. The electrical and structural properties of crystals obtained by these various techniques are compared.