Effects of p-type conductive properties of triaxial strain-regulated ZnO (S, Se, Te) system

Abstract

P-type ZnO materials are a difficult problem worldwide. The strain caused by doping, substrate and sample lattice constant mismatch, and thermal expansion coefficient mismatch is often ignored. First principle calculation is used to select the appropriate strain range and solve this problem. The effect equivalent to the actual strain is simulated to study the conductive properties and the mechanism of a doping system. Studies have shown that under unstrained conditions, the binding energies of undoped ZnO and all doped systems are negative, and the stability is relatively high. The formation energy of all doped systems increases, and their stability decreases with the increase in tensile strain or compressive strain. This study shows for the first time that when the compressive strain is −5%, the hole mobility of the same doping systems of Zn36SO35, Zn36SeO35, and Zn36TeO35 is relatively maximum. The difference between the hole concentration of the Zn36MO35 (M = S, Se, Te) systems is extremely small regardless of tensile strain or compressive strain. When the compressive strain is −5%, the hole conductivity of the Zn36SO35 system is the best. These findings can serve as guide in the experimental design and preparation of new p-type ZnO conductive functional materials.