Extraction of Material Parameters by Transmission Spectra of AIGaN Film

To study the optical properties of multilayer AIGaN films with high Al content and calculate the relevant optical parameters, we fitted the transmission spectra of two samples based on the method of the multilayer-film transfer matrix. According to the mechanism of the AIGaN materials absorbing the incident light on different wavelengths, considering the out-of-band weak absorption of the materials, we established an absorption coefficient model in the all-band range (200-800 nm). At the same time, the root mean square (RMS) parameter of surface roughness was introduced to characterize the effect of the surface roughness of the materials on the transmission spectra. Furthermore, the transmission spectra of two Al0.63Ga0.33 N samples with different structural parameters were fitted by the proposed model, and the fitting results were in good agreement with the experimental results. The absorption coefficient of Al0.63Ga0.33 N material in the all-band range provided reliable experimental data for the study of the response spectra of solar-blind UV detectors. Additionally, the parameters such as film thickness, refractive index, and surface roughness of the N materials were also obtained.

Automated summary

This study investigated the optical properties of multilayer AIGaN films with high Al content, fitting transmission spectra and establishing an absorption coefficient model. The effects of surface roughness on the transmission spectra were characterized using root mean square (RMS) parameters, and the fitting results were in good agreement with experimental results. Experimental data on the absorption coefficient of Al0.63Ga0.33N material in the all-band range were provided for the study of solar-blind UV detectors' response spectra, along with obtaining parameters of film thickness, refractive index, and surface roughness of the N materials.