Effect of Diffusion Temperature on the some Electrical Properties of CdS:In Thin Films Prepared by Vacuum Evaporation

CdS films were prepared by thermal evaporation technique at thickness 1 µm on glass substrates and these films were doped with indium (3%) by thermal diffusion method. The electrical properties of these have been investigated in the range of diffusion temperature (473-623 K)> Activation energy is increased with diffusion temperature unless at 623 K activation energy had been decreased. Hall effect results have shown that all the films n-type except at 573 and 623 K and with increase diffusion temperature both of concentration and mobility carriers were increased.

Studies on (SBA-15)-AgI Host-Guest Nanocomposite Materials

SBA-15 molecular sieve owned the characteristic of uniform nanoscale channels, large pores, thick walls and high hydrothermal stability. It has the potential foreground as adsorption, separation, catalysis and new type host-guest nanocomposite materials. In this paper, SBA-15 molecular sieve was synthesized in acidic medium by hydrothermal method using triblock copolymers (EG20PG40EG20) as template, tetraethoxysilane as silica resource. Semiconductor material AgI was incorporated into the mesoporous channels of the SBA-15 molecular sieve by solid phase thermal diffusion method and the (SBA-15)-AgI nanocomposites materials were prepared. The products were characterized by means of powder X-ray diffraction, low-temperature nitrogen adsorption-desorption technique at 77 K and luminous properties were studied. The results showed that AgI went into the channels of the SBA-15, the materials (SBA-15)-AgI remained the highly ordered two-dimensional hexagonal. However, the crystalline was decreased to some degree, the pore volume, pore size and the surface area decreased to some extent compared to those of the SBA-15 molecular sieve. It was found by luminous studies that the energy band gap of the (SBA-15) -AgI composite material is very high and radiation process is very strong. The composite materials possess very good luminous performance and can be hopefully acted as luminous materials.

Study of Electrical Conductivity and Microcosmic Structure of Tetrahedral Amorphous Carbon Films Doped by Boron

A type of tetrahedral amorphous carbon (ta-C) film that was doped by boron (ta-C:B) is focused on in this paper. The ta-C film is prepared by filtered cathodic vacuum arc (FCVA) technique and then doped with boron using the thermal diffusion method. Then the microcosmic structure and electrical conductivity of the ta-C are characterized by an X-ray photoelectron spectroscopy (XPS) method and four-probe method, respectively. The results show that the conductivity of ta-C:B is significantly increased; the resistivity decreases from 1.5 × 106 Ω·cm to 350 Ω·cm approximately, while the percentage of sp3bonds in the film is changed from 87% to 60% approximately. It means that this type of film preserved the mechanical characteristics of diamond-like carbon (DLC) films and improved the electrical characteristics greatly at the same time.