Accession Number : AD0726647

Title :   Electronic Properties of Oxide Insulators.

Descriptive Note : Final scientific rept. 16 Mar 69-15 Apr 71,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS SCHOOL OF CHEMISTRY

Personal Author(s) : Wertz,John E.

Report Date : MAY 1971

Pagination or Media Count : 8

Abstract : Studies of the point defects in the alkaline earth oxides MgO, CaO, and SrO centered upon the trapped-electron of F-type centers, the trapped-hole or V1-type centers and the various valence states of substitutional impurities. Attempts have been made to correlate numerous other electronic properties - optical absorption, luminescence behavior, charge-release, phenomena, and the Hall coefficient with electron spin data. Largely, the behavior has been in accord with prediction, but with some surprises; for example, the F center in MgO was observed to give a photo-induced Hall effect appropriate to holes as the majority carrier, whereas for the CaO and SrO one finds electrons, as expected. This is attributed to the very-low lying ground state of the F center in MgO, i.e., the level lies in the vicinity of the valence band. Two substitutional defects recently studied are the Fe(3+) ion and the Ti(3+) ion in MgO, both with an associated cation vacancy in the next-nearest neighbor cation position. These represent almost ideally simple examples of d1 and/or d5 ions in octahedral-plus-tetragonal symmetry. Recent theoretical studies have been made of the hole trapped adjacent to a positive ion cavancy in order to determine the extent to which the localized model is applicable. Present results are not conclusive. (Author)

Descriptors :   (*ALKALINE EARTH OXIDES, ELECTRON PARAMAGNETIC RESONANCE), MAGNESIUM OXIDES, CALCIUM OXIDES, STRONTIUM COMPOUNDS, COLOR CENTERS, BAND THEORY OF SOLIDS, SEMICONDUCTORS, HALL EFFECT, LUMINESCENCE, IMPURITIES

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE