Ultrathin Crystal Research Articles

X-Ray studies on single crystal films of BaTiO3

Abstract Epitaxial crystals of BaTiO3 have been grown by activated reactive evaporation. The ultra-thin crystal less than 100 A thickness shows an elongation along the c-direction. The elongation of the crystal is discussed in terms of an electronic space charge at the surface layer in the ferroelectric semiconductor.

Transient stimulated hyper-Raman scattering in an organic crystal.

Transient stimulated hyper-Raman scattering has been observed in an ultrathin organic crystal (-)2-(\ensuremath{\alpha}-methylbenzylamino)-5-nitropyridine (MBA-NP) pumped by picosecond laser pulses. Results were modeled by an instability theory.

An ultrahigh vacuum single crystal adsorption microcalorimeter

The design of an ultrahigh vacuum microcalorimeter enabling calorimetric heats of adsorption to be obtained on single crystal surfaces as a detailed function of coverage is discussed. The system comprises a pulsed supersonic molecular beam source, an ultrathin metal single crystal, and remote infrared temperature sensing. Sticking probabilities and coverages are determined pulsewise by the King and Wells method, and heat capacity calibrations are conducted in situ by laser beam pulsing. Results for CO and O2 on Ni{110} demonstrate excellent sensitivity to adsorption of ∼10−13 moles of gas (∼0.01 monolayer). The heat capacity of the calorimeter is 4.2 μJ K−1.

Single crystal adsorption microcalorimetry

An ultrahigh vacuum microcalorimeter has been developed which enables calorimetric heats of adsorption to be obtained on single-crystal surfaces, as a detiled function of coverage. The system comprises a pulsed supersonic molecular beam source, an ultrathin metal single crystal, and remote infrared temperature sensing. Sticking probabilities and coverages are determined pulse-wise by the King and Wells method, and heat capacity calibrations are conducted in situ by laser beam pulsing. Results for oxygen on Ni{110} demonstrate excellent sensitivity to 0.01 monolayer pulses.

Growth, structure and energetics of ultrathin ferromagnetic single crystal films on Mo(110)

The growth mode, structure and thermal stability of ultrathin Fe, Co and Ni films on Mo(110) surfaces is studied by Auger electron spectroscopy, low energy electron diffraction, work function change measurements at various temperatures at and above room temperature and by thermal desorption spectroscopy. In all cases pseudo-Frank-van der Merwe growth is found near room temperature, Stranski-Krastanov growth at intermediate temperatures and alloying at higher temperatures. In Co and Ni films structural rearrangements during growth occur already in the submonolayer range, in Fe films only towards the end of the second monolayer. Implications for the study of magnetic properties are discussed.

Development of Ultra Thin Crystal Resonator Unit

Development of Ultra Thin Crystal Resonator Unit