Ionicity of the chemical bond in A^IB^IIIC semiconductors

Abstract

The Phillipsvan Vechten dielectric theory for binary tetrahedral compounds and Levine's extension of this theory to multibond crystals is used to evaluate the bond ionicities in the AIBIIICZI chalcopyrite compounds with A1 = Cu, Ag from spectroscopic data. I n deriving the ionicity of the AI-CVI bond the influence of the noble metal d electrons it taken into account. The results obtained are compared with previous estimations.Die dielektrische Theorie von Phillips und van Vechten fur binare tetraedrisoh koordinierte Verbindungen und die Erweiterung dieser Theorie durch Levine auf Kristalle mit mehreren Bindungen werden ausgenutzt, urn die Bindungsionizitaten in den AWIICBI-Chalkopyritverbindungen mit A1 = Cu, Ag aus spektroskopischen Daten zu Lerechnen. Rei der Herleitung der Ionizitiit der AI-CVI-Bindung wird der EinfluB der d-Elektronen der Edelmetalle beriicksichtigt. Die erhaltenenResultate werden mitfriiheren Abschatzungen verglichen.

Dielectric properties of I-III-VI2-type chalcopyrite semiconductors

“…Calculated results are summarized in Table I present work with previously calculated results for Cu-based I-III-VI 2 -type compounds, 17,21 is summarized in Table III. The large differences between the results calculated by different authors can be ascribed to the following facts.…”

“…17,21 ͑3͒ Different methods are used to treat (Z VI )*. The present work determines the value for (Z VI )* on the basis of its bond graph; the two types of bonds are treated differently.…”

“…Previous calculations [16][17][18][19][20][21] on this topic have shown important contributions from d electrons to the I u VI bonds in chalcopyrite compounds, yet these works have not given us an explanation of their NLO behaviors. In the present work we will follow the principal assumptions made previously [16][17][18][19][20][21] and treat d electrons as addition to the valence electrons of the type I ions that participate in the formation of I u VI bonds. The contributions from these modified I u VI bonds to the total linear ͑i.e., refractive indices n o ) and second-order nonlinear ͑i.e., nonlinear optical susceptibility tensor coefficients d 36 ) optical responses of these I-III-VI 2 type chalcopyrite semiconductors will be quantitatively scaled.…”

About the average bond ionicity in AIBIIIC compounds

“…I n order t o evaluate f i = f i , x from (1) and (2) and the relations for cop, EF and E , (NEUMANN 1983) Ro-MAND et al). The average bond ionicities f i = f,,v obtained on the basis of this data and relation (3) are given in Table 1, too.…”

Infrared reflectivity of ZnIn2Te4

“…Since the bond-stretching force constants are essentially determined by the corresponding bond lengths (NEUMANN 1989) they should be nearly equal in all compounds because their B1"-CV1 bo nd lengths differ only slightly from compound to compound: 0.2765 nm in CuInTe, (HAWORTH, TOMLINSON), 0.2756 nm in AgInTe, (HAHN et al 1953), 0.2650nm in ZnIn,Te, and 0.2752nm in HgIn,Te, (HAHN et al 1955). The same is approximately true for the bond ionicities that are determined by the respective ,electronic susceptibilities and bond lengths (NEUMANN 1983). If the general considerations of LEVINE are extended to the A"B' :' CI' ordered-vacancy compounds their high-frequency dielectric constant should be given by…”