Optical and structural properties of synthesized ZnO nanorods through chemical bath deposition on various substrates

Chemical bath deposition was used to synthesize ZnO nanorods (NRs) on glass and fluorine_doped tin oxide (FTO) substrates. X-ray diffraction was performed to examine the crystallinity of ZnO nanorod. Results showed that ZnO NRs had a wurtzite crystal structure. Field emission scanning electron microscopy images showed that glass sample had rod-like structure distribution with (50 nm) diameter and average length of approximately (700 nm), whereas the FTO-coated glass sample had 25 nm diameter and average length of approximately 950 nm. The direct optical transition band gaps of the glass and FTO_coated glass samples were( 4 and 4.43 eV), respectively. The structural and optical properties of the synthesized ZnO products were described. The grown ZnO NRs have good optical properties. The proposed method is simple, inexpensive, soft, and environmentally friendly compared with other methods, making it appropriate for the large-scale manufacturing of devices and other app1ications.

Selective 4H-SiC UV Detectors

Carcinogenic (bactericidal) radiation (λ = 200–300 nm with a peak at 254 nm) is present in natural (Sun) and artificial (lamps) source of UV radiation. Its intensity is very low as compared to other types of radiation, but it strongly affects the health of human beings. To prevent oncological diseases, it is important to monitor the carcinogenic radiation level; i.e., selective photodetectors are required. A UV photodetectors based on n-4H-SiC Schottly barriers and p+-n junctions are proposed. The quantum efficiency spectrum of such detectors is very close to the spectrum of relative action of carcinogenic radiation on human beings due to the direct optical transition at 4.9 eV in 4H-SiC. The quantum efficiency (at the spectral peak 254 nm) amounts to about 0.3 electrons/photon for virtually zero sensitivity in other spectral regions. Quantum efficiency in the wavelength range 247–254 nm is practically independent of temperature in the range from −100 to +300°C.

Optical Properties of Al- and Sb-Doped CdTe Thin Films

Nondoped and (Al, Sb)-doped CdTe thin films with 0.5, 1.5, and 2.5 wt.%, respectively, were deposited by thermal evaporation technique under vacuum onto Corning 7059 glass at substrate temperatures () of room temperature (RT) and 423 K. The optical properties of deposited CdTe films such as band gap, refractive index (n), extinction coefficient (), and dielectric coefficients were investigated as function of Al and Sb wt.% doping, respectively. The results showed that films have direct optical transition. Increasing and the wt.% of both types of dopant, the band gap decrease but the optical is constant asn, and real and imaginary parts of the dielectric coefficient increase.