Unusual bandgap bowing in highly mismatched ZnOS alloys: Atomistic tight-binding band anti-crossing model
Saad M Alqahtani, Muhammad Usman, Shaikh S Ahmed
Journal of Applied Physics | AMER INST PHYSICS | Published : 2019
An atomistic band anticrossing (BAC) model is developed and used to study “unusual bowing” in energy bandgap and its dependence on the material composition in minority O anion-alloyed ZnS (ZnS1−xOx) and minority S anion-alloyed ZnO (ZnO1−xSx) highly mismatched alloys. For dilute O in ZnS1−xOx, it is found that the bandgap decreases as the O composition is increased. A “down-shift” in the conduction band edge (CBE) of host ZnS, which arises from an interaction between the CBE and the localized O defect state, is identified as the root cause. However, the reduction in bandgap as a function of dilute S composition in the ZnO1−xSx alloy follows an “up-shift” in the valence band edge (VBE) of hos..View full abstract
Awarded by U.S. National Science Foundation
This work was financially supported by the U.S. National Science Foundation (Grant No. 1610474). S. M. Alqahtani would like to acknowledge the support from Saudi Arabian Cultural Mission (SACM).