Effect of Al0.1Ga0.9As thickness on the structural, optical, thermal, and electrical properties of (Al0.1 Ga 0.9As)/GaAs heterojunctions

Al0.1Ga0.9As nano-films of various thicknesses were deposited on GaAs substrate and examined using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), UV-Visible spectrophotometry, Photoluminescence (PL), Electrochemical Impedance Spectroscopy (EIS), and Photothermal Deflection (PTD). The PTD technique is used to analyze the effect of Al0.1Ga0.9As thickness on thermal properties and showed its sensitivity to weak structural changes. By increasing the Al0.1Ga0.9As thickness, the crystallinity was degraded, an infrared emission centered at 997.4 nm whose intensity is the highest for 50 nm was observed. A pn junction was formed for thicknesses higher than 400 nm, the band gap was increased from 1.59 to 1.68 eV. The thermal conductivity increased from 35.3 to 37.3 W m- 1 K-1 and the thermal diffusivity increased from 0.195 to 0.22 cm2 s-1. As a result of this investigation, the Al0.1Ga0.9As/GaAs can be considered for potential applications in photoelectric and thermoelectric devices.