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Wide range of techniques used to obtain fundamental optical and optoelectronic properties of CZTS single crystals grown by vapour transport.

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The concentration of trace elements has been measured for dental enamel from 86 healthy human teeth using particle-induced X-ray emission (PIXE). The majority of the teeth (n = 70) were collected from dentists in the county of Oxfordshire in the United Kingdom, although a smaller group (n = 16) were collected from Cornwall. The elements K, Ca, Mn, Fe, Co, Ni, Cu, Zn, Sr, Pb, and Hg have been detected and statistically analyzed by grouping according to sex, age, and geographical location. The concentrations of Fe and Cu were found to be lower in the teeth from female donors (P < 5%) and are believed to result from the continued burden of blood loss during menstruation. Strong positive correlations (P < 0.1%) were found between Ca, Co, Ni, and Zn for all groups; these elements were also found to exhibit a negative correlation (P < 1%) with age for teeth from female donors. This is believed to be related to decalcification during the menopause. Pb was found to exhibit a positive correlation (P < 5%) with age for both sexes, and is believed to substitute for Ca in the Ca hydroxy apatite (HAP) within the dental enamel.

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The optical constants have been determined for films of CdSxTe1-x over the wavelength range 250-3200 nm. The films were prepared by vacuum evaporation from solid solutions. Rutherford backscattering spectrometry has been employed to determine the thickness of the films, which is in the range 1390-2430 nm, and x-ray diffraction has been used to determine the phase and lattice parameters. The films were found to be cubic for x<0.65, and hexagonal for x>0.65. Reflectance and transmittance measurements have been made over the wavelength region 250-3200 nm, and a model, which includes the effects of coherent scattering, has been used to determine the complex refractive index in the transparent region. A singly subtractive Kramers-Kronig algorithm is derived for use with reflectance data of equal wavelength spacing. This novel Kramers-Kronig transform has been used to determine the optical constants in the opaque region. Polynomial functions are supplied which describe the variation of refractive index and extinction coefficient with wavelength. The photon energies required for both direct and indirect transitions have been found by least-squares fitting to the absorption spectra. The results are compared with previous work on 40 nm thick films.

A rapid screening methodology for the development of transparent conducting oxides is presented. The methodology, based on a combination of spectrophotometry, ellipsometry and 4-point probe measurements, was used to map out the opto-electronic properties over a co-sputtered ZnO : Al2O3 film deposited from separate ceramic targets of ZnO and Al2O3. Clear distributions for the carrier density, n e, and mobility, μ e, are determined as a function of wt%. Al2O3 content within the film. A minimum resistivity value of 7.6 × 10−4 Ω cm was achieved for a composition of 1.5 wt%. Al2O3.