Vapor growth of Bi12GeO20, γ-Bi2O3 and BiOCl
Abstract
The chemical vapor deposition of Bi12GeO20, γ-Bi2O3, and BiOCl in an open tube system is reported. BiOCl crystals were deposited by the hydrolysis of BiCl3 with H2O at temperatures of 750-800°C. γ-Bi2O3 formed at temperatures of 787-790°C as dendrites and oriented deposits on Bi12GeO20 substrates from the oxidation of Bi vapor with N2O. In depositing Bi12GeO20 using Bi vapor and GeCl4, it is necessary to employ multiple oxidants (N2O and H2O). Deposits of Bi12GeO20 on Bi12GeO20, sapphire, spinel, quartz and MgO were polycrystalline. It is shown that the compound Bi12GeO20 can be grown having a range of compositions, Bi12 + yGexO20 in which x can vary at least between 1 2 < x < 2. In attempts to vapor grow Bi12GeO20 the reaction of the deposit with substrates and reactor parts is observed and remains a major obstacle to growing this material in single crystal films. © 1973.