The chemical shifts of the Ge 3d, 3p3/2,1/2 and Se 3d, 3p3/2,1/2 photoelectron lines were measured for the amorphous Ge–Se system and those of the Ge photoelectron lines are corrected for Auger parameter shifts. According to the valence shell potential model, the ratio of the chemical shift in the amorphous Ge–Se system to that in stoichiometric GeSe2 can be approximated by the ratio of the Ge–Se bond number in the Ge–Se system to that in GeSe2. The chemical shift ratios evaluated from the experimental results reveal bond structures at non-stoichiometric compositions. In the excess-Ge range, GeSe is composed of atomic clusters of three-fold co-ordinated Ge and Se atoms, and Ge2Se3 contains atomic clusters of Se3Ge–GeSe3 units. In the excess-Se range, GeSe3 includes GeSe4 tetrahedral units, and Se–Se chains and/or Se8 rings.

Using a semi-classical approach, we describe an on-chip cooling protocol for a micro-mechanical resonator by employing a superconducting flux qubit. A Lorentz force, generated by the passive back-action of the resonator's displacement, can cool down the thermal motion of the mechanical resonator by applying an appropriate microwave drive to the qubit. We show that this onchip cooling protocol, with well-controlled cooling power and a tunable response time of passive back-action, can be highly efficient. With feasible experimental parameters, the effective mode temperature of a resonator could be cooled down by several orders of magnitude. Contents

X-ray phototelectron spectroscopy was used to determine the binding energies of the core electrons in Ag- or Cu-doped amorphous As2Se3 films. Chemical shifts of the constituent elements indicate the electron transfer from Ag or Cu to As and Se upon doping. Charged defects are induced to As-Se bonds. The mechanism of the migration of Ag and Cu in amorphous As2Se3 is discussed.

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Amorphous GeSe, GeSe2 and GeSe3 films were investigated by XPS. Binding energies and chemical shifts of the 3d and 3p electrons of the constituent elements were measured. It was found that obliquely-deposited GeSe3 films contain four(Ge)-two(Se) fold and three(Ge)-three(Se) fold bondings, while normally-deposited films have the former type bonding alone. Photo-induced chemical shifts of obliquely-deposited GeSe3 films are attributable to a transformation from the four(Ge)-two(Se) fold bonds to the three(Ge)-three(Se) bonds. The mechanism of thephoto-induced effect is described.