A new method for the determination of optical band gap and the nature of optical transitions in semiconductors

Effect of the degree of inversion on optical properties of spinel ZnFe2O4

“…The optical band gaps were determined by the derivation of absorption spectrum fitting method (DASF). 33 Optical spectra of normal and inverse ZFO were calculated using the Vienna ab initio Simulation Package (VASP) 34 version 5.4.4. A carefully converged quasi-particle GW0 35 algorithm was employed and to gain insight about the optical properties, the Bethe-Salpeter-Equations (BSE) 36 were solved afterwards.…”

Optical and Thermal Properties of Some Tellurite Glasses

“…Figure 2 represented the (DASF) [14], d{ln[A(λ)/λ]}/d(1/λ) versus (1/λ) for the present glass samples. The optical energy gap will be calculated according to the (DASF) model [14] by using relations (4-6):…”

“…Where h is Planck's constant and c is the velocity of the light and the values of Urbach energy, ∆E in eV can be obtained in the (DASF) method [14] from the slope of the linear region of the ln (A/λ) − (1/λ) curves as shown in Figure 2 (A, B, C, D). The optical energy gap will be calculated by using Eq.(4).…”

“…In Tauc's method [11,12], absorption coefficient (α) requires measurement of the absorbance, reflectance, and thickness of the film. Recently, the absorption spectrum fitting method (ASF) and derivation of absorption spectrum fitting (DASF) methods have been introduced to obtain the band gap avoiding the film thickness measurement which commonly could not be measured precisely [13,14]. Also, tellurite glasses with high thermal and glass stabilities were suggested as potential materials to realize highly efficient fibers [15][16][17][18][19][20].…”

Synthesis and characterization of K2Pr2O(BO3)2: structural, spectroscopic and thermogravimetric investigations of a novel potassium praseodymium oxoborate structure-type

“…3) demonstrates bandgap values of 4.40(1) eV and 4.50(1) eV for an indirect and [37]. Recently, the derivation of absorption spectrum fitting (DASF) method was proposed by Souri et al [38] for thin films to calculate the bandgap energies without any presumption of the nature of the transition. Notably, the DASF method can also be expressed as follows proposed by Kirsch et al [39,40] for powder samples:…”