Fundamental Optical Properties of Materials II

Decoding the Atomic Structure of Ga2Te5 Pulsed Laser Deposition Films for Memory Applications Using Diffraction and First-Principles Simulations

“…Basically, the overall shape of the absorption coefficient α is reminiscent of the behavior observed in materials such as silicon or carbon [67,68]. This shape is typically associated with direct optical transition at higher photon energies hν and indirect optical absorption at lower hν [68][69][70][71][72]. Assuming direct optical transition in crystallized Ga 2 Te 5 above 1.3 eV,…”

“…the direct optical bandgap was found to be E d g = 1.36 ± 0.03 eV, Figure 4c. The constant A in Equation ( 11) is given by A ≈ e 2 / n R ch 2 m * e (2m * ) 3/2 , where e is the electron charge and m * is a reduced electron and hole effective mass [69]. The derived optical absorption coefficient α, presented in Figure 4b, exhibits two optical processes above and below the incident photon energy ℎ𝜈 ≈ 1.3 eV.…”

“…Assuming direct optical transition in crystallized Ga2Te5 above 1.3 eV, 𝛼ℎ𝜈 = 𝐴(ℎ𝜈 − 𝐸 ) / , (11) the direct optical bandgap was found to be 𝐸 = 1.36 ± 0.03 eV, Figure 4c. The constant 𝐴 in Equation ( 11) is given by 𝐴 ≈ [𝑒 /(𝑛 𝑐ℎ 𝑚 * )](2𝑚 * ) / , where 𝑒 is the electron charge and 𝑚 * is a reduced electron and hole effective mass [69].…”

“…Basically, the overall shape of the absorption coefficient α is reminiscent of the behavior observed in materials such as silicon or carbon [ 67 , 68 ]. This shape is typically associated with direct optical transition at higher photon energies and indirect optical absorption at lower [ 68 , 69 , 70 , 71 , 72 ]. Assuming direct optical transition in crystallized Ga 2 Te 5 above 1.3 eV, the direct optical bandgap was found to be = 1.36 ± 0.03 eV, Figure 4 c. The constant in Equation (11) is given by , where is the electron charge and is a reduced electron and hole effective mass [ 69 ].…”

Solid state field-assisted diffusion of silver in multi-component tellurite glasses

“…8 shows the absorption spectra of glass substrate (solid black line) and the glass after SSFA diffusion at 300°C (solid red line). The absorption edge shifts to the longer wavelength after diffusion probably due to the broadening of the valence band as a result of the strong coupling of Ag + d-electron orbitals with O 2-p-electron orbitals [15]. The absorption coefficient (α) also increases slightly in the transparent region partially owing to the increased refractive index.…”