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We have studied the effect of growth temperature on the growth mode and defect density of (LaxY1−x)2O3/Si(111) and Si(111)/(LaxY1−x)2O3/Si(111) heterostructures by transmission electron microscopy. We have also investigated the epitaxial relationships between fluorite and bixbyite oxides on different Si surfaces in the framework of a model which suggests that the mismatch between the oxygen sublattice and the Si substrate is the most important criterion for establishing the epitaxial relation. In addition, during attempts to achieve perfect lattice matching between (LaxY1−x)2O3 and Si by incorporating lanthanum beyond the near-lattice matched composition, we observe the formation of a phase-separated microstructure. A strain energy argument is developed to explain this observation.

A series of GaN:Mg structures were grown in molecular beam epitaxy, using either one or two rf nitrogen sources, and in metalorganic chemical vapor deposition systems with varying Mg flux. Acceptor energies were measured using the Hall effect and admittance spectroscopy techniques. The acceptor energies were found to be different for the two methods, i.e., 135–155 meV for the Hall effect measurement and 80–115 meV for the admittance spectroscopy measurement. The apparently small acceptor energies from the admittance spectroscopy measurement were explained, through a simulation process, by the combined effects of (1) high Mg acceptor concentration with no other free carrier sources, and (2) the Mg emission kinetics assisted by the Frenkel–Poole field effect in the GaN:Mg structures.

We demonstrate the potential for ultrathin aluminum-oxide films as alternate gate dielectrics for Si complementary metal–oxide–semiconductor technology. Films are deposited in ultrahigh vacuum utilizing atomic beams of aluminum and oxygen on Si(100) surfaces. We show device-quality Si(100)/Al2O3 interfaces with interfacial trap densities in the 1010 cm−2 eV−1 range, and with leakage current densities five orders of magnitude lower than what is observed in SiO2 insulators at the same equivalent electrical thickness. As-grown films possess an amorphous-to-microcrystalline structure, depending upon the deposition temperature, and any interfacial layers between the Si(100) and Al2O3 layer are

This invention provides a novel hybrid organic-inorganic semiconductor light emitting diode. The device consists of an electroluminescent layer and a photoluminescent layer. The electroluminescent layer is an inorganic GaN light emitting diode structure that is electroluminescent in the blue or ultraviolet (uv) region of the electromagnetic spectrum when the device is operated. The photoluminescent layer is a photoluminescent organic thin film such as tris-(8-hydroxyquinoline) Al, Alq3, deposited onto the GaN LED and which has a high photoluminescence efficiency. The uv emission from the electroluminescent region excites the Alq3 which photoluminesces in the green. Such a photoconversion results in a light emitting diode that operates in the green (in the visible range). Other colors such as blue or red may be obtained by appropriately doping the Alq3. Furthermore, other luminescent organics in addition to Alq3 may be used to directly convert the uv or blue to other wavelengths of interest. The invention provides the benefits of simplicity and ease of fabrication, since a complete redesign of the structure is not necessary to change emission wavelength, and the possibility for making displays by spatially varying the deposition of the emissive layer.

Measurements of the polar Kerr rotation and optical coercivity as a function of photon energy have been made on ≊2 μm thick ThMn12‐type crystalline sputtered films of Sm(Fe,Ti)12. The optical coercivity for a Ti containing (222) textured film was 3.10 kOe at a photon energy of 1.25 eV, 2.96 kOe at 1.84 eV, and 2.92 kOe at 2.45 eV. The optical coercivity for a similar composition (002) textured Sm(Fe,Ti)12 film was relatively constant at 1.24 kOe. These samples were measured in air at 300 K without any protective overcoating. The polar Kerr rotation observed for these crystalline films versus the photon energy paralleled that observed for pure Fe. The magnetometer and optical coercivities for the (222) textured Sm(Fe,Ti)12 films were 1.5 and 2.5 times as large, respectively, as for similar composition (002) textured films. Differences in grain sizes incorporated during the direct synthesis of the films onto heated substrates are needed to account for the large differences observed in the coercivities for the (222) versus (002) textured films.

Amorphous thin films of UxAs100−x are ferromagnetic for U‐rich compositions, 49≤x≤75, with a magnetic moment of 0.2 to 0.4 μB per U atom and Curie temperatures, Tc, up to 120 K. Large resistivities are found at 5 K for compositions x

The energy band gap, the band alignment with Si, and the chemical bonding of 4–5 nm thick (TbxSc1−x)2O3 dielectric films were investigated as a function of composition. Films with x=0, 0.5, and 1 were prepared by a molecular beam deposition technique on silicon substrates. The structure of the dielectric films was characterized by high resolution transmission electron microscopy. We found that upon deposition, a silicate and a silicon oxide layer were formed at the dielectric/silicon interface for all compositions. X-ray photoelectron spectroscopy was used to determine the band gap, as well as the energy band alignment with Si and the chemical structure of the films. Energy gap values of 6.0±0.2 and 7.5±0.2 eV were obtained for pure Sc2O3 and Tb2O3, respectively, while for the mixed layer (x=0.5) a value of 6.8±0.2 eV was extracted. It was found that the valence band offset does not change with Sc addition to Tb2O3, while the conduction band offset increases with x, from a value of 2.9±0.2 eV for the x=0 ...

We have discovered a class of phase separated materials in which the two phases couple antiferromagnetically across the phase boundary. A prototypical example is cobalt containing ≂100‐A‐diam precipitate particles of EuS with the NaCl structure. These materials show many of the properties of ferrimagnets such as compensation points so we have adopted the term ‘‘macroscopic ferrimagnet’’ to distinguish them from ferrimagnets in which the antiferromagnetic exchange couples individual atoms. As a result of the ferrimagnetic exchange between the Co and the EuS the net magnetization of the composite is low in the vicinity of compensation so the anisotropy field is high. Electron beam evaporated thin films have a perpendicular easy axis as a result of growth induced anisotropy. Another effect of the exchange between the Co and EuS is to order the EuS well above its normal Curie point of 16 K. A film with 80 mole % Co and 20 mole % EuS has a compensation point of 55 K showing that the Eu2+ has essentially its fu...

The electron‐trapping characteristics of W in SiO2 have been studied using evaporated and ion‐implanted W. The evaporated W results indicate a trapping cross section varying from 1.56×10−14 to 4.62×10−14 cm2 depending on the evaporation time. The cross section of the implanted W is 1.06×10−15 cm2. Thermal‐detrapping measurements indicate an activation energy of 0.9 eV, whereas optical detrapping is not observed for light energies up to 6 eV. It is not understood why there is this large discrepancy of results. It is also interesting to note that Powell and Beairsto measured a barrier height of 3.6 eV for the W‐SiO2 interface.