Effect of annealing on the mechanical properties of GaSb films produced by pulsed laser deposition

Abstract

Mechanical deformation and crystallization processes in GaSb thin films were investigated under varying annealing conditions, revealing significant enhancements in mechanical properties. The hardness and indentation modulus increased markedly after annealing, which was attributed to the reduction in free volume and the onset of crystallization. Additionally, the fracture toughness (K_IC) was found to decrease with increasing annealing temperature, highlighting a trade-off between the hardness and toughness. Nanoindentation tests in the annealed films showed crack formation and further revealed the formation of deformation twins and Lomer-Cottrell locks, which enhanced the strength of the film by restricting dislocation mobility. The as-deposited film consisting of an amorphous matrix containing nanocrystals showed remarkable plasticity, with no cracking or delamination but shear bands. These findings deepen the understanding of the mechanical behavior of GaSb thin films and highlight their potential applications in phase-change memory devices, where thermal and mechanical stability are crucial.