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In this work, the Si layer is deposited on the SiC complex substrate which is composed of Si(111) substrate and 3C-SiC film grown on it. These Si and 3C–SiC films grown under different temperatures in a chemical vapor deposition system are analyzed. The crystalline orientation, the crystalline quality and the conduction type of the films are measured by X-ray diffraction, Raman scattering ,Scanning electron microscope, and 1150 ℃ is found the optimized temperature for the epitaxial growth of SiC film grown on the carbonized layer. Measurement results also show that the epitaxial layer is n-type 3C-SiC which has the same crystalline orientation with the Si (111) substrate. Si film grown on the SiC complex substrate under the temperature of 690 ℃ has the best crystalline quality. This film is composed of p-type monocrystal Si and has the same crystalline orientation with the substrate.

The Ge mole fraction (x) of Si1-xGex layer was described by the C-V technique for Schottkey contact of single heterojunction Si1-xGex/Si, whose structure profile can be characterized by SEM image and EDS. Then the strained Si cap layer was grown on the Si1-xGex/Si, and C-V technique was used to determine the carrier concentration and structure of double heterojunction Si/Si1-xGex/Si. The change of the structure between Si1-xGex/Si and Si/ Si1-xGex/Si was also observed by this method.

In this paper we have characterized the performance of a vertical metalorganic chemical vapor deposition (MOCVD) reactor used for deposition of ZnO thin films. The equations of the mathematical model are solved numerically using a control-volume-based finite difference method. A two-dimensional model is put forward to study the dependence of the growth rate on the inlet flow rate and susceptor temperature. The mass-fraction distribution of the reactants has been studied as a function of the position above the substrate, which shows that gas phase pre-reaction in our reactor is well confined. The simulation results are useful for the practical growth of ZnO.

The weak-localization of the two-dimensional electron gas (2DEG) in a modulation-doped Al0.22Ga0.78N/GaN single quantum well has been investigated through the magnetoresistance measurements. The elastic scattering time τε, dephasing time τφ and spin-orbit(s-o) scattering time τso at various temperatures are obtained. The fitting parameters indicate that the inelastic scatterings to the 2DEG are mainly due to the piezoelectric field and the alloy disorder in the AlxGa1-xN barrier. When the second subband in the triangular quantum well at the heterointerface is occupied by the 2DEG, the anti-weak localization is observed clearly, which is due to the strong spin-orbit interaction. The spin-orbit effect dominates the quantum correction of the conductivity in the upper subband. The intersubband scattering becomes stronger with increasing temperature.

The morphology evolution of ZnO films grown on sapphire (0001) by MOCVD have been studied as a function of buffer growth time and temperature by means of atomic-force microscope (AFM), x-ray diffractions (XRD) and optical microscopy. When the buffer growth temperature decreased to 450℃, the surface became smooth greatly, indicating the transition from typical 3D island growth to quasi-2D growth mode. As the buffer growth time exceeds 5min, the micron-sized pit-like features are formed. It is due to the lack of stabilization of adatoms under the “etching” action of ionized O2/Ar during high temperature buffer annealing

Infrared reflectivity measurements of GaN1-xPx alloys and quantitative fittings using Lorentz model have been carried out. In the GaN1-xPx alloys, two competitive mechanisms that determine the carrier concentration have been put forward. The one is from the effect of the isoelectronic traps which decrease the carrier concentration while the other is from the effect of defects which increase the carrier concentration. The calculated results of imaginary part of the elastivity of GaN and GaN1-xPx alloys show that the longitudinal optical phonon-plasmon (LPP) modes shift to high frequency direction and its linewidth gradually broadens with increasing carrier concentration in GaN1-xPx, indicating that the coupling of LPP modes gradually enhances and the damping of LPP modes gradually augments.

The MOCVD-growth and annealing of InN films have been studied in this work. The XRD spectra of InN films grown at 350 ºC~500 ºC indicate that the diffraction of In increases with increasing the growth temperature to 425 ºC and the temperature higher than 425 ºC causes the decrease of In diffraction. The corresponding SEM images show that In grains disappear from the surface as the growth temperature is higher than 425 ºC. These are attributed to the increase of the desorption of In with the growth temperature. In addition, the SEM images of the annealed InN films also show that the In grains decrease gradually as the annealing temperature is higher than 425 ºC. Thus, it is concluded that the desorption of In is the main process as the temperature is higher than 425 ºC.

High quality GaN layers were grown on Si(111) substrates using high-temperature-grown AlN as buffer layer by rapid thermal process low-pressure metalorganic chemical vapor deposition. The growth and characteristics of AlN buffer layer and the GaN layers were investigated by using scanning electron microscope, X-ray diffraction, photoluminescence (PL), Raman scattering, and Hall measurements at room temperature. It was found that pre-seeding Al to Si surface is a critical condition for AlN growth on Si. Two-dimensional growth of AlN was achieved under optimized conditions. Raman scattering shows a narrow GaN E2peak and broad AlN E2, E1peaks. At room temperature, the investigated films are unintentionally doped n-type. The carrier concentration is about 1.3×1017cm−3and the Hall mobility is about 210cm2/Vs. Metal–semiconductor–metal photoconductive detectors were fabricated on the GaN/Si(111) films. These detectors show a sharp cut-off wavelength at 363nm. A maximum responsivity of 6.9A/W was achieved at 357nm under a 5.0V bias. These results indicate that high quality GaN films on Si(111) can be obtained using the AlN buffer layer, and the potential application of GaN films based on Si substrates.

High quality GaN layers were grown on Si(1 1 1) substrates using high-temperature-grown AlN as buffer layer by rapid thermal process low-pressure metalorganic chemical vapor deposition. The growth and characteristics of AlN buffer layer and the GaN layers were investigated by using scanning electron microscope, X-ray diffraction, photoluminescence (PL), Raman scattering, and Hall measurements at room temperature. It was found that pre-seeding Al to Si surface is a critical condition for AlN growth on Si. Two-dimensional growth of AlN was achieved under optimized conditions. Raman scattering shows a narrow GaN E 2 peak and broad AlN E 2 , E 1 peaks. At room temperature, the investigated films are unintentionally doped n-type. The carrier concentration is about 1.3×10 cm and the Hall mobility is about 210 cm/V s. Metal-semiconductor-metal photoconductive detectors were fabricated on the GaN/Si(1 1 1) films. These detectors show a sharp cut-off wavelength at 363 nm. A maximum responsivity of 6.9 A/W was achieved at 357 nm under a 5.0 V bias. These results indicate that high quality GaN films on Si(1 1 1) can be obtained using the AlN buffer layer, and the potential application of GaN films based on Si substrates.

Using frequency-dependent admittance spectroscopy, the dynamics characteristics of tunneling into charge-tunable silicon quantum dots (Si-QDs) with a SiO2/Si- QDs/SiO2/Si-substrate structure are investigated. Two resonance peaks, both for capacitance and conductance in the inversion region, are observed at room temperature, being attributed to the direct tunneling between the conductance band of Si-substrate and the lowest two electronic state levels of the Si-QD. Moreover, the Coulomb charging energy of the dots is extracted from the experimental results.

In this paper we reported the results on the low-temperature thermal oxidation of Si nanowires. Various polygon-shaped Si nanowires with linewidths between 100 and 300 nm were fabricated on Si/Si1—xGex/Si heterostructure substrates by using lithography, reactive ion etching, and subsequent selective chemical etching. We find that oxidized Si nanowires following 750 and 775 °C wet oxidation will keep the same shape as the initial unoxidized samples, and all the SiO2 boundaries of oxidized samples will arrive at a circular shape. These results, which should be due to stress effects, provide useful information for understanding the behavior of non-planar oxidation that is used in modern Si nanoelectronic technology.

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