Zn-doped SnO2 nanoparticles were synthesized using the sol-gel method, employing tin chloride pentahydrate (SnCl4 & centerdot;5H(2)O) and zinc nitrate hexahydrate (Zn(NO3)(2)& centerdot;6H(2)O) as precursors, with a 5% Zn-to-Sn molar ratio. Acetic acid was used as a stabilizing agent, and the obtained gel was thermally treated at 400 degrees C to yield Zn-doped SnO2 nanoparticles. X-ray diffraction (XRD) analysis confirmed the tetragonal rutile phase of SnO2, with slight lattice distortion attributed to Zn incorporation and the associated formation of oxygen vacancies. Fourier transform infrared (FTIR) spectroscopy verified the presence of Zn-O and Sn-O bonding. UV-Vis spectroscopy revealed a red-shift in the absorption edge and a bandgap of 3.50 eV, indicating slight bandgap narrowing due to defect-induced states. Photoluminescence (PL) studies showed both near band-edge and defect-related emissions, confirming the presence of oxygen vacancy related states. The I-V characteristics exhibited linear (Ohmic) behavior at low bias and nonlinear behavior at higher bias, consistent with space-charge-limited conduction (SCLC). The combined structural, optical, and electrical results indicate that Zn doping effectively modifies the electronic structure and defect landscape of SnO2 nanoparticles, suggesting potential for optoelectronic and photocatalytic applications.
Sm3+-doped BaZnGeO4 phosphors with various Sm3+ doping concentration were synthesized via a high-temperature solid-state method. X-ray diffraction (XRD) confirmed the single-phase BaZnGeO4 structure with no impurities. Photoluminescence spectra showed concentration quenching behavior, where dipole-dipole interactions were identified as the main energy transfer mechanism between Sm3+ ions. Thermal stability analysis revealed that the thermal quenching of the Sm3+ (4)G(5/2) level follows a crossover process, with an activation energy (Delta E) of 0.24 eV, as described by the Arrhenius model. Additionally, Judd-Ofelt analysis provided the optical transition probabilities and radiative characteristics of Sm3+ in the BaZnGeO4 host, with calculated Omega(lambda) (lambda = 2, 4, 6) values of 6.83 & times; 10(-20) cm(2), 5.10 & times; 10(-20) cm(2), and 2.80 & times; 10(-20) cm(2).
Optoelectronic techniques offer non-invasive tools for assessing pigmented skin lesions by quantifying wavelength-dependent interactions between light and cutaneous chromophores. This pilot study evaluated hyperspectral imaging as an objective method for identifying dysplastic features in melanocytic nevi through pixel-level analysis of melanin distribution. Ten patients with clinically diagnosed nevi located on the back, arms, legs, or neck were examined using a pushbroom hyperspectral system operating in the 400-800 nm range. Images were normalized with white and dark references, cropped to the lesion region of interest, denoised, and processed with in-house software to generate melanin concentration maps based on the modified Beer-Lambert law. The spatial uniformity of melanin distribution was quantified using semivariance, applied as a numerical indicator of local heterogeneity. Common nevi showed homogeneous melanin maps and semivariance values below 0.1, whereas histopathologically confirmed dysplastic nevi presented irregular melanin distribution and values above 0.24. These preliminary results suggest that hyperspectral imaging combined with semivariance analysis may differentiate common from dysplastic nevi objectively, without relying on artificial intelligence or large training datasets. Further validation in larger cohorts is required to establish diagnostic thresholds and clinical applicability and to determine its future potential value as a complementary screening tool in routine dermatological practice.
The paper presents the production of a heteroepitaxial GaP layer on a Si(111) substrate using a buffer, continuous epitaxial layer (Si-2)(1-x)(GaP)(x) 0 <= x <= 1 from a tin solution-melt. The generalized moments of the components of the solid solution (Si-2)(1-x)(GaP)(x) were calculated and it was shown that the formation of epitaxial layers is more probable: m**GaP=3.96856 & centerdot;10(-9) C/m and m**Si-2=2.55856 & centerdot;10-9 C/m. The single crystallinities of the grown epitaxial layers are investigated. The triangles formed at the beginning of growth on the surface of the Si substrate show that the (Si-2)(1-x)(GaP)(x )layers began to grow in the direction with the orientation (111). Structural study showed an increase in the lattice period of the film a((Si2)1-x(GaP)x)=0.54619 +/- 0.00004 nm relative to Si (a(Si) = 0.54307 +/- 0.00004 nm) and GaP (a(GaP)=0.54451 +/- 0.00004 nm), which is explained by the arising compressive stresses along the plane of the epitaxial layers. SEM analyses confirmed the presence of Si, Ga, P components in the (Si-2)(1-x)(GaP) film. Using CoreAFM, nanosized height nanoscale islands with a size of 50-60 nm and nano-pits with a depth of 8 nm on the surface of the (Si-2)(1-x)(GaP) film were detected. The films had n-type conductivity with a concentration of n=5 center dot 10(18) cm(-3 )and a mobility of & micro;=80 cm(2)center dot V-1 center dot sec(-1 )of charge carriers at 300 K. The film thicknesses varied within 15-30 & micro;m depending on the growth conditions. The photosensitivity of the pSi-n(Si-2)(1-x)(GaP)(x) structure covered the spectral range of 1.1 divided by 2.58 eV.
Our research will investigate the effect of quantum dots (QDs) sizes of Cadmium Selenide (CdSe) on the all-optical switching phenomena. The study was carried out using two continuous wave lasers, a pump green laser (lambda = 532 nm) and a probe red laser (lambda = 635 nm). The results of our work have shown that the size of CdSe QDs effect has a strong influence on the alloptical switching phenomena. The size of the QDs effect is used as an efficient way to control the all-optical switching processes. Our results show that a strong pump beam can modify the low-power probe beam by generating diffraction ring patterns, which confirms the possibility of changing and modifying the probe's laser beam signal standardise as OFF/ON through nonlinear optical switching processes.
