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Stabilizing Cu2S in its ideal stoichiometric form, chalcocite, is a long-standing challenge that must be met prior to its practical use in thin-film photovoltaic (PV) devices. Significant copper deficiency, which results in degenerate p-type doping, might be avoided by limiting Cu diffusion into a readily formed surface oxide and other adjacent layers.(More)
Field emission from a solid metal surface has been continuously studied for a century over macroscopic to atomic scales. It is general knowledge that, other than the surface properties, the emitted current is governed solely by the applied electric field. A pin cathode has been used to study the dependence of field emission on stored energy in an L-band rf(More)
RATIONALE Although the fundamental physical limits for depth resolution of secondary ion mass spectrometry are well understood in theory, the experimental work to achieve and demonstrate them is still ongoing. We report results of high-resolution TOF SIMS (time-of-flight secondary ion mass spectrometry) depth profiling experiments on a nanolayered(More)
Xin Zhang,1 Mengqun Li,2 Jeff Walter,1 Liam O’Brien,1,3 Michael A. Manno,1 Bryan Voigt,1 Frazier Mork,1 Sergey V. Baryshev,4,5 James Kakalios,2 Eray S. Aydil,1,* and Chris Leighton1,† 1Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA 2School of Physics and Astronomy, University of(More)
We report results of high-resolution sputter depth profiling of an alternating MgO/ZnO nanolayer stack grown by atomic layer deposition (ALD) of ≈5.5 nm per layer. We used an improved dual beam time-of-flight secondary ion mass spectrometer to measure (24)Mg(+) and (64)Zn(+) intensities as a function of sample depth. Analysis of depth profiles by the(More)
In this communication, we report results of a high resolution sputter depth profiling analysis of a stack of 16 alternating MgO and ZnO nanolayers grown by atomic layer deposition (ALD) with thickness of ∼5.5 nm per layer. We used an improved dual beam approach featuring a low energy normally incident direct current sputtering/milling ion beam (first beam).(More)
Undesirable electron field emission (also known as dark current) in high gradient rf photocathode guns deteriorates the quality of the photoemission current and limits the operational gradient. To improve the understanding of dark current emission, a high-resolution (∼100  μm) dark current imaging experiment has been performed in an L-band photocathode gun(More)
A new projection type imaging system is presented. The system can directly image the field emission site distribution on a cathode surface by making use of anode screens in the standard parallel plate configuration. The lateral spatial resolution of the imager is on the order of 1-10 μm. The imaging sensitivity to the field emission current can be better(More)
A device and a method for producing ultrashort electron pulses with GHz repetition rates via pulsing an input direct current (dc) electron beam are provided. The device and the method are based on an electromagnetic-mechanical pulser (EMMP) that consists of a series of transverse deflecting cavities and magnetic quadrupoles. The EMMP modulates and chops the(More)