Atomic Layer Deposition and Strain Analysis of Epitaxial GaN-ZnO Core-Shell Nanowires

We demonstrate theepitaxial coating of GaN NWs with an epitaxialZnO shell by atomic layer deposition at 300 & DEG;C. Scanning transmissionelectron microscopy proves a sharp and defect-free coherent interface.The strain in the core-shell structure due to the lattice mismatchand different thermal expansion coefficients of GaN and ZnO was analyzedusing 4D-STEM strain mapping and Raman spectroscopy and compared totheoretical calculations. The results highlight the outstanding advantagesof epitaxial shell growth using atomic layer deposition, e.g., conformalcoating and precise thickness control.