Preparation and characterization of atomically clean, stoichiometric surfaces of AIN(0001)

Abstract

In situ exposure of the (0001) surface of AlN thin films to flowing ammonia at 1120°C and 10 −4 Torr removes oxygen/hydroxide and hydrocarbon species below the detectable limits of x-ray photoelectron spectroscopy and decreases the Al/N ratio from 1.3 to 1.0. The positions of the Al 2p and the N 1s core level peaks acquired from the cleaned surfaces were 75.0± 0.1 eV and 398.2± 0.1 eV, respectively, which were similar to the values determined for the as-loaded samples. The cleaning process left unchanged the ͑1 ϫ 1͒ low energy electron diffraction pattern, the step-and-terrace microstructure, and the root mean square roughness values observed for the surfaces of the as-loaded samples; i.e., the surface structure and microstructure were not changed by the high-temperature exposure to ammonia at low pressures. Vacuum annealing under 10 −7 Torr at 1175°C for 15 min removed all detectable hydrocarbons; however, it did not remove the oxygen/ hydroxide species.

Polarization Effects of GaN and AlGaN: Polarization Bound Charge, Band Bending, and Electronic Surface States

“…In fact, most experimental band bending experiments for n-type Ga-face GaN typically report measurements between 0.3 eV and 1.5 eV. [21][22][23] These measurements can then determine the concentration of charged surface states from the band bending, where…”

Recovery of Valuable Materials from End-of-Life Photovoltaic Solar Panels

“…The most intense peak of the O 1s spectrum at 532.68, as shown in Figure 4 h, characterizes the formation of Ag 2 O. For the Alunite/K-alum mixture, the high-resolution Al 2p and O 1s XPS spectra ( Figure 4 c,d), show two peaks located at 75.139 eV for Al and 533.05 eV for O, which is within the range of the alumina binding energy [ 26 , 27 ]. Moreover, the sharp peaks at 296.99 and 294.1 eV are characteristic of K 2p2/3 and 2p1/2, respectively.…”