Papers by Keyword: Si Doping

Abstract: The high-Al-content Al_xGa_1-xN alloys, x>0.70, and AlN is the fundamental wide-band-gap material system associated with the technology development of solid-state LEDs operating at the short wavelengths in the deep-UV (λ < 280 nm). Yet, their properties are insufficiently understood. The present study is intended to bring elucidation on the long-time debated and much speculated Si transition from shallow donor in GaN to a localized deep DX defect in Al_xGa_1-xN alloys with increasing Al content. For that purpose electron paramagnetic resonance is performed on a particular selection of high-Al-content epitaxial layers of Al_0.77Ga_0.23N, alternatively Al_0.72Ga_0.28N, alloy composition.

Abstract: Electrical characteristics of Pt Schottky contact formed on semipolar (11-22) n-type GaN planes with different Si doping concentration were investigated. Large Si doping to semipolar (11-22) n-GaN led to improved electrical and structural properties, e.g., the Hall mobility (μ) was increased by 35 % and the full width at half maximum (FWHM) of X-ray rocking curves with X-ray incident beam direction of [-1-12 was decreased by 34 %. Thermionic field emission (TFE) theory applied to the forward current-voltage (I-V) curves of fabricated Pt Schottky diodes yielded the Schottky barrier height (Φ_B) of 1.64 and 1.84 eV, the tunneling parameter (E₀₀) of 44 and 65 meV, and the ideality factor (n) of 1.83 and 2.57 for the lowly doped and highly doped samples, respectively, indicating that the Si doping affected the carrier transport properties substantially associated with the change of surface states density.

Abstract: Ge2Sb2Te5 thin films and Si doped Ge2Sb2Te5 thin films were deposited by electron beam evaporation method. The crystallization behaviors of the films were investigated by using the in situ resistance measurement. Through in situ resistance measurement, the increases of amorphous stability, crystallization rate and crystalline resistivity after Si doping were observed. The promoted nucleation process and the retardation of crystal growth were found in Si doped samples through the calculation of JMAK equation.

Abstract: Si doped CVD diamond films are prepared on Si substrate by means of hot filament chemical vapor deposition (HFCVD) through adding tetraethoxysilane (TEOS) into acetone as source of reactant gas during the growth process. The samples of diamond films are investigated by scanning electron micrograph (SEM), Raman spectrum, X-ray diffractometry (XRD) and surface profiler. The experimental results show that compared with pure diamond film, Si doped CVD diamond film exhibits grain refinement and smoother surface. Then selective area deposition (SAD) of B-doped diamond films are achieved on both Si doped CVD diamond film and pure CVD diamond film with silicon dioxide layer as sacrificial layer. SEM investigation demonstrates that the boundary of patterning on pure diamond film is rather fuzzy while on pure diamond film it is trim and distinct, which is mainly attributed to the relatively low surface roughness.

Abstract: Boron Phosphide (BP) layers have been grown on Si (100) as a substrate for cubic GaN heteroepitaxy. Si heavy doping was attempted to reduce the threading dislocation density in the BP. To observe the effect on dislocations in BP by Si doping, we used cross-sectional transmission electron microscopy (XTEM). Also, Glow Discharge-Optical Emission Spectroscopy (GDOES) were used to evaluate the effect of Si doping. For the samples under the conditions (a) and (e), we found the formation of pits at BP surface and an increasing in the proportion of threading dislocations with an angle of 90 ° to the surface. We could not see a significant change in the threading dislocation density by Si doping under the conditions used in this paper.