Negative electron affinity and electron emission at cesiated GaN and AlN surfaces
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چکیده
Ž . Ž . The electronic structure of GaN and AlN 0001 surfaces and modification by cesium Cs adsorption are investigated via Ž . Ž . ultra-violet and X-ray photoemission spectroscopy UPS, XPS and total yield spectroscopy. The electron affinity EA of the clean and ordered 1=1 surfaces is found to be equal to 3.3 and 1.9 eV for GaN and AlN, respectively. Cs adsorption Ž . with the help of oxygen pre-treatment in the case of GaN reduces EA on both surfaces by about 2.6–2.8 eV, leading to true Ž . negative electron affinity NEA in the case of AlN and effective NEA in the case of GaN. Total yield spectroscopy confirms NEA on both surfaces. q 2000 Elsevier Science B.V. All rights reserved. PACS: 73.20.At; 68.45.Da
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تاریخ انتشار 2000