Characterization of biaxial stress and its effect on optical properties of ZnO thin films

Abstract

Biaxial stress of ZnO film deposited on quartz was measured by side-inclination x-ray diffraction technique, indicating that the film is subjected to a tensile stress. One part of the stress is induced by thermal mismatch between the ZnO and the quartz and increases with annealing temperature, while another part results from lattice mismatch and is about 1.03GPa. The optical band gap of the ZnO film shows a blueshift with increasing biaxial tensile stress, opposed to the change of the band gap with biaxial tensile stress for GaN. The mechanism of the stress-dependent band gap is suggested in the present work.

Influence of oxygen/argon ratio on structural, electrical and optical properties of Ag-doped ZnO thin films

“…For p-type samples at P O2 Z0.75, the c-axis lattice constants are much larger than the value of 0.5203 nm of undoped ZnO. It has been reported that ZnO film grown on quartz is subjected to biaxial tensile stress due to large thermal mismatch between film and substrate, which result in decrease of the lattice constant c of the films [17]. Thus, the increase of the c-axis lattice constant cannot stem from stress but substitution of some Ag for Zn in the films due to the larger ionic radius of Ag + (1.26Å) than that of Zn 2 + (0.74Å) [18,19].…”

Influence of Zn/O ratio on structural, electrical and optical properties of ZnO thin films fabricated by plasma-assisted molecular beam epitaxy

“…When the ZnO film is fabricated at nonstoichiometric ratio, there exist excessive zinc or oxygen atoms in the ZnO film. A previous literature [15] indicates that the excessive Zn or O driven by the biaxial stress can move to the surface and produce a lot of defects at the surface, leading to the formation of rough surface with reticulated structures. However, when the ZnO Fig.…”

Study on preheating and annealing treatments to biomimetic non-smooth cast iron sample with high thermal fatigue resistance

“…The measured residual stresses were along the laser scanning direction, and the selected entrance angle of X-ray was 0 • , 21.3 • , 30.9 • and 39 • , respectively. The residual stresses ( ) were calculated by the following equation [21]:…”