BARC/PUB/2021/0515

 
 

Effect of Oxygen and Aluminum Incorporation on the Local Structure of GaN Nanowires: Insight from Extended X-ray Absorption Fine Structure Analysis

 
     
 
Author(s)

Parida, S.; Sahoo, M.; Abharana, N.; and others
(A&MPD)

Source

Journal of Physical Chemistry-C, 2021. Vol. 125 (5): pp. 3225-3234

ABSTRACT

A thorough investigation of local structure, influencing the macroscopic properties of the solid, is of potential interest. We investigated the local structure of GaN nanowires (NWs) with different native defect concentrations synthesized by the chemical vapor deposition technique. Extended X-ray absorption fine structure (EXAFS) analysis and semiempirical and density functional theory (DFT) calculations were used to address the effect of dopant incorporation along with other defects on the coordination number and bond length values. The decrease of the bond length values along preferential crystal axes in the local tetrahedral structure of GaN emphasizes the preferred lattice site for oxygen doping. The preferential bond length contraction is corroborated by the simulations. We have also studied the impact on the local atomic configuration of GaN NWs with Al incorporation. AlxGa1−xN NWs are synthesized via novel ion beam techniques of ion beam mixing and post-irradiation diffusion process. The change in the local tetrahedral structure of GaN with Al incorporation is investigated by EXAFS analysis. The analysis provides a clear understanding of choosing a suitable process for ternary III-nitride random alloy formation. The study of the local structure with the EXAFS analysis is corroborated with the observed macroscopic properties studied using Raman spectroscopy.

 
 
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