Ce/GaN(0001) interfacial formation and electronic properties
X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy electron diffraction have been used to study the growth, interfacial reaction, and Fermi level movement of Ce on a n-type GaN(0001)-(1×1) surface. The results demonstrate that Ce grows in a layer-by-layer-like mode and reacts with the substrate at the interface, leading to formation of metallic Ga at room temperature. With increasing Ce coverage, a downward Fermi level movement is observed, and the resultant Schottky barrier height is 1.3 eV. Annealing promotes further diffusion and thus interfacial Ce–Ga exchange reaction.
Abstract Calculations employing the simple Monte Carlo model of gamma-ray interaction in a silicon ΔE -detector provide a very reliable energy spectrum of Compton-scattered electrons. This makes it possible to determine the thickness of a Si ΔE -detector with a good accuracy.