The ionic substitutions have been proposed as a tool to improve the biological performance of hydroxyapatite (HAp) based materials. In the present work, the systems of Ca(10-x)Mgx(PO4)6(OH)2 (MgHAp, x = 0, 1, 2, and 3) were successfully synthesized by solgel method. To obtain nanocrystalline of MgHAp, the prepared precursors were calcined in air at 600 °C for 2 h. The samples were characterized by Xray diffraction (XRD) and transmission electron microscope (TEM) observation. The XRD results confirm the formation of pure phase of HAp with the lattice parameter a in the range of 0.94170.9479 nm and c of 0.68410.6919 nm. The crystallite sizes of the powder are found to be 3546 nm as evaluated by the XRD line broadening method. The morphology of the samples are spherical shape of diameter less than 100 nm as evaluated by TEM. The corresponding selected area electron diffraction (SAED) analysis further confirms the formation of hexagonal structure of HAp.

Structural properties of lattice-matched InGaPN on GaAs (001) have comprehensively investigated by high resolution X-ray diffraction (HRXRD), Raman spectroscopy, and atomic force microscopy (AFM). The InGaPN layers were grown by metal organics vapor phase epitaxy (MOVPE). To obtain the lattice-matched InGaPN on GaAs, flow rates of trimethylindium (TMIn), trimethylgallium (TMGa) were kept, respectively, at 14.7 and 8.6 mol/min. On the other hand, the N content optimized by varying the flow rate of dimethyhydrazine (DMHy, N precursor) was controlled at 300 mol/min. With a combination of HRXRD and Raman scattering measurements, the In and N contents are estimated to be 55.8 and 0.9 at%, respectively. The lattice-mismatch lower than 0.47%, which corresponds to the lattice-matching condition, was confirmed for all the layers. The rapid thermal annealing (RTA) process was performed to improvement the crystalline quality of InGaPN layers. The annealing temperature was fixed at 650 ∘ C, which is an optimum growth temperature of a GaAs buffer layer. The annealing time was varied in a range of 30 to 180 s to verify a composition uniformity. With increasing the annealing time up to 120 s, the In and N contents were slightly increased. The AFM-root mean square (RMS) roughness of the InGaPN surface was observed to be reduced. For higher annealing times, the N content was dramatically reduced, whereas the In content was still remained. Moreover, the RMS roughness was observed to be increased. RTA at 650∘ C for 120 s demonstrated a significant improvement of structural properties of the lattice-matched InGaPN layers on GaAs (001).K e y w o r d s: InGaPN, RTA, HRXRD, MOVPE, Raman scattering.

The preparation and characterization of nickel oxide (NiO) thin film for electrochromic smart window applications are studied. The NiO thin film was prepared by the DC magnetron sputtering from a pure nickel target. The sputtering power was varies in the interval 50–200 W. The crystallinity and physical morphology of NiO films are characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), respectively. The XRD result revealed that polycrystalline NiO thin films with preferred growth directions along (111) and (200) planes are obtained. Moreover, the electrochromic property of NiO thin films was investigated with a UV-Visible spectrophotometer. The colored state of the electrochromic cell was obtained by the ion insertion at the 1-V external applied bias in 0.1 M KOH. The reversibility between the colored and bleached states is confirmed by the optical transmittance. The result shows the optical contrast as high as 28.68.