Improved Treatment of Photothermal Cancer by Coating TiO2 on Porous Silicon.

In present society, the technology in various field has been sharply developed and advanced. In medical technology, especially, photothermal therapy and photodynamic therapy have had limelight for curing cancers and diseases. The study investigates the photothermal therapy that reduces side effects of existing cancer treatment, is applied to only cancer cells, and dose not harm any other normal cells. The photothermal properties of porous silicon for therapy are analyzed in order to destroy cancer cells that are more weak at heat than normal ones. For improving performance of porous silicon, it also analyzes the properties when irradiating the near infrared by heterologously junction TiO2 and TiO2NW, photocatalysts that are very stable and harmless to the environment and the human body, to porous silicon. Each sample of Si, PSi, TiO2/Psi, and TiO2NW/PSi was irradiated with 808 nm near-IR of 300, 500, and 700 mW/cm2 light intensity, where the maximum heating temperature was 43.8, 61.6, 67.9, and 61.9 degrees C at 300 mW/cm2; 54.1, 64.3, 78.8, and 68.9 degrees C at 500 mW/cm2; and 97.3, 102.8, 102.5, and 95 0C at 700 mW/cm2. The time required to reach the maximum temperature was less than 10 min for every case. The results indicate that TiO2/PSi thin film irradiated with a single near-infrared wavelength of 808 nm, which is known to have the best human permeability, offers the potential of being the most successful photothermal cancer therapy agent. It maximizes the photo-thermal characteristics within the shortest time, and minimizes the adverse effects on the human body.

Thermal evolution characterizatics of atomic layer deposition prepared TiO2 interfacial layer by synchrotron radiation X-ray scattering.

TiO2 thin film prepared by the atomic layer deposition (ALD) with supplies of Ti(O-i-Pr)4 and H2O have been analyzed using the difference X-ray reflectivity (DXRR). The thickness of buried interfacial layer (IL) embedded in between Si-substrate and TiO2 layer was characterized as a function of temperatures of 20, 300, and 500 degrees C mounted on an in-situ hot stage The growth rate of TiO2 film was estimated to be 0.5 nm/cycle at the temperature of 150 degrees C. It was identified that the interfacial layer of the treated thin film was disappeared at a certain temperature rise. Furthermore, we found that the crystalline structure of TiO2 film was varied depending on not only the growth temperature but also the post thermal treatment of the samples. Since the synchrotron radiation X-ray scattering measurement allow us to investigate the atomic structure evolution in the range of a few nanometer thick, nondestructively, in this letter we report its characteristics of the thermal evolution of the TiO2 interfacial layer that is the crucial step for progress in microelectronics and nanotechnology.