Nanoscratch study of Zn1−xMnxO heteroepitaxial layers

We investigated the nanotribological properties of Zn1−xMnxO epilayers (0 ≤ x ≤ 0.16) grown by molecular beam epitaxy (MBE) on sapphire substrates. The surface roughness and friction coefficient (μ) were analyzed by means of atomic force microscopy (AFM) and hysitron triboscope nanoindenter techniques. The nanoscratch system gave the μ value of the films ranging from 0.17 to 0.07 and the penetration depth value ranging 294–200 nm when the Mn content was increased from x = 0 to 0.16. The results strongly indicate that the scratch wear depth under constant load shows that higher Mn content leads to Zn1−xMnxO epilayers with higher shear resistance, which enhances the Mn–O bond. These findings reveal that the role of Mn content on the growth of Zn1−xMnxO epilayers can be identified by their nanotribological behavior.