Photoacoustic measurements of optical energy gap of porous silicon as a two layer opaque material

摘要: Photoacoustic (PA) technique was applied to study the optical absorption and measure energy gap of porous silicon (PSi) as a suitable example two layer samples (porous Si substrate). The PSi layers were prepared by electrochemical anodization etching process with different current density p-type wafers. formation has been identified photoluminescence (PL) AFM measurements. Thermal diffusivity also measured confirm thermal isolation properties formed PSi. absorption, gap, investigated analyzing experimental data from PA values have found be porosity-dependent. In contrast conventional techniques, measures band both simultaneously high accuracy. range porosity (27–52%) studies, our results show that band-gap (1.7–1.92 eV) higher than obtained for substrate (1.11 eV). These energies used obtain diameter quantum dots in layer. introduce candidate depth profile analysis multilayer solids. Moreover, can particles size estimation low dimensional materials.