UV-induced defect formation in cubic ZrO2. Optical demonstration of Y, Yb and Er dopants interacting with photocarriers

Optical Properties of Various Strontium Bismuthates: Luminescence and UV‐induced Photocoloration

“…Regardless, the UV-induced response of all three bismuthates could nonetheless be rationalized in terms of a mechanistic model presented elsewhere. [36,37] As evidenced in Figure 7, the UV-induced ΔA(hν) spectra are rather broad, with their intensities and shapes changing with the excitation wavelength. Deconvolution of the ΔA(hν) spectra of the Sr 2 Bi 2 O 5 and Sr 3 Bi 2 O 6 bismuthates into Gaussian components are illustrated in Figure S3.…”

“…In addition, the concentration of photocarriers, and consequently the efficiency of formation of color centers in the sublayer at a depth d L � 1/L (L is the diffusion length of the carriers) and/or the depth of the space charge region, differ from that in the bulk. [37,38] Typically, d L < d α ; i. e., less than the "bulk" sublayer. Accordingly, the efficiency of formation of color centers within the L sublayer is strongly affected by adsorbed species, [36][37][38][39] and may change with altering the wavelength of the actinic light through a change of the d α (λ)/d L ratio.…”

“…[37,38] Typically, d L < d α ; i. e., less than the "bulk" sublayer. Accordingly, the efficiency of formation of color centers within the L sublayer is strongly affected by adsorbed species, [36][37][38][39] and may change with altering the wavelength of the actinic light through a change of the d α (λ)/d L ratio. Note that the red spectral limits of photocoloralion occur at wavelengths longer than 505 nm (2.4 eV) and 420 nm (2.9 eV), respectively, for Sr 2 Bi 2 O 5 and Sr 3 Bi 2 O 6 ( Figure 7).…”

“…[40]). In such case, [36,37] the sign of ΔA at sufficiently long irradiation times is determined by the initial concentrations of the deep traps (N 0 ). The relationship between the initial concentration of the color centers (D 0 ) and pseudo-first-order constants of a given carrier trapped by a defect (p) with the recombination of a trapped carrier with a free carrier of the opposite sign (q; eqns.…”

“…ðno effect of irradiationÞ (10) Accordingly, taking into account the features of all three samples to the same subclass of bismuthates within the framework of the photocoloration model [36,37] outlined above, one can infer that the condition in eqn. 8 is valid for Sr 2 Bi 2 O 5 and Sr 3 Bi 2 O 6 , (i. e., 0 � D 0 < N 0 ), while the condition in eqn 9, which is close to that of eqn.…”