In biological systems, organic molecules exert a remarkable level of control over the nucleation and mineral phase of inorganic materials such as calcium carbonate and silica, and over the assembly of crystallites and other nanoscale building blocks into complex structures required for biological function. This ability to direct the assembly of nanoscale components into controlled and sophisticated structures has motivated intense efforts to develop assembly methods that mimic or exploit the recognition capabilities and interactions found in biological systems. Of particular value would be methods that could be applied to materials with interesting electronic or optical properties, but natural evolution has not selected for interactions between biomolecules and such materials. However, peptides with limited selectivity for binding to metal surfaces and metal oxide surfaces have been successfully selected. Here we extend this approach and show that combinatorial phage-display libraries can be used to evolve peptides that bind to a range of semiconductor surfaces with high specificity, depending on the crystallographic orientation and composition of the structurally similar materials we have used. As electronic devices contain structurally related materials in close proximity, such peptides may find use for the controlled placement and assembly of a variety of practically important materials, thus broadening the scope for 'bottom-up' fabrication approaches.

The reaction of Ti(NMe(2))(4) with 2 equiv of Me(3)SiN(3) in toluene solution affords a dark red polymeric material of composition [Ti(NMe(2))(2)(N(3))(2)](n) (1). If the reaction is carried out in pyridine (py) solution, dark red, crystalline [Ti(NMe(2))(2)(N(3))(2)(py)(2)] (2) is formed. Analogous reactions of Ti(NMe(2))(4) with 2 or 1 equiv of Me(3)SiN(3) in the presence of 1 equiv of bipyridyl (bipy) in toluene solution afford brown crystals of [Ti(NMe(2))(2)(N(3))(2)(bipy)] (3) and dark red crystals of [Ti(NMe(2))(3)(N(3))(bipy)] (4), respectively. Crystallographic data for 2: orthorhombic, C222(1), a = 7.120(1) Å, b = 15.899(3) Å, c = 16.946(4) Å, V = 1918.3(6) Å(3), rho = 1.310 g/cm(3), Z = 4. Crystallographic data for 3: monoclinic, I2/a, a = 7.358(2) Å, b = 16.808(4) Å, c = 14.837(6) Å, beta = 95.40(2) degrees, V = 1826.8(1) Å(3), rho = 1.368 g/cm(3), Z = 4. Crystallographic data for 4: monoclinic, P2(1)/c, a = 15.682(2) Å, b = 8.814(1) Å, c = 15.128(1) Å, beta = 108.39(1) degrees, V = 1984.2(4) Å(3), rho = 1.267 g/cm(3), Z = 4. Compounds 1 and 2 deposit thin films of titanium nitride (TiN) on silica and/or nickel substrates in the temperature range 300-400 degrees C. The TiN films deposited from precursor 2 are superior to those deposited from 1.

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Ultrathin (8–23 Å) silicon oxynitrides have been studied in the temperature range of 560–1000 °C in 4 Torr of NO using a sequential growth and analysis approach. X-ray photoelectron spectroscopy indicates that with increasing growth temperature and time, a bonding structure with predominantly Si–O rather than Si–N formation is favored. Simultaneously, the average volume fraction of N (N/N+O) in the dielectric decreases, as a consequence of which the N1s binding energy increases by 0.2–0.8 eV from its initial value of 397.8 eV at a thickness of 8 Å. A correlation of the electrical characteristics of NO grown oxynitrides with nitrogen content and location has been made. A film growth mechanism that takes into account the removal of previously incorporated N by NO is also proposed.

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