We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

Ion implantation was used to form high densities (~1019 /cm3) of small oxide precipitates in Ni in order toinvestigate the strength mechanism produced by such highly refinedstructures. Nanometer-size precipitates of Al2O3 andNiO are found to block dislocation motion in the Ni matrix, producing yieldstrengths up to 4.6 GPa, more than twice that of hardened bearing steel.Dispersion strengthening theory, developed for micrometer-size precipitatesand spacings, was found to account quantitatively for the yield strengthsproduced by nanometer-size oxides as well. Nanoindentation plusfinite-element modeling was used to quantify the mechanical properties ofimplanted metal layers, and was extended to examination of amorphous Silayers formed by self-ion implantation. The amorphous phase was found tohave a yield strength of 4.45 ± 0.20 GPa, Young's modulus of 144 ± 7 GPa,and hardness of 10.3 ± 0.4 GPa. The modulus and hardness are reduced by 10%and 15%, respectively, from those of crystalline Si.

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

The microstructures of Si ion-implanted with Cu have been characterized by TEM after annealing. For 1.2 at.%, the Cu is trapped at planar defects, but for 10 at.%, η-Cu3Si forms, allowing Cu to diffuse at its equilibrium solubility. These observations allow proper evaluation of the binding energies of Cu to previously formed internal cavities (2.2 eV) and η-Cu3Si (1.7 eV). The η-Cu3Si in the 10 at.% layer catalyzes oxidation of the Si. The microstructures also indicate that Si implanted with ~2 at.% Cu reforms epitaxially with embedded defects after 8 hr. at 700°C, but for ~10 at.% Cu, epitaxy is not recovered after 6 hours at 600ºC.

The microstructuTe and mechanical properties of high purity aluminum implanted with 20 at.% oxygen to a depth of roughly 500 nm and subjected to various thermal histories have been examined. Transmission electron microscopy and Rutherford-backscattering spectrometry were used to characterize the depth and nature of the implanted zone. As implanted, the material appears to contain a homogeneous distribution of disordered precipitates with sizes of 1.5-3.5 nm. Annealing at 450 or 550ΰC for 1 hour, induces ordering of the precipitates but only causes slight coarsening. Ultra-low load indentation hardness testing was used to probe the mechanical response of the surface-modified material. The data from the hardness tests were interpreted through the use of a finite-element model; the results indicate the flow stresses of an implanted and annealed layer are as high as 1600 MPa. The as-implanted material is much harder, approaching 3300 MPa. The degree of strengthening expected for the as-implanted and post-annealed material on the basis of the observed microstructure was estimated using several micromechanical models, and the results conform to the findings from indentation testing.