Papers by Keyword: LEIS

Abstract: With the increasing use of III-nitride semiconductors, more knowledge is needed about the manufacturing processes and reactions with different chemicals. Gallium nitride semiconductors show a different behavior in wet chemistry compared to the known silicon technologies [4,5]. The different behavior can be explained, among other things, by the polar axis in the c-direction [0001] [6]. Surface characterization is necessary to gain a better understanding of the native surface and after different processes. We have used Low Energy Ion Scattering (LEIS) with its very high sensitivity for surface characterization to characterize the surface of different gallium nitride semiconductors and to establish a depth profile by sputtering [1,8].

Abstract: Local electrochemical technique was used to measure the impedance of austenite in AISI 304 stainless steel under tensile strain of 0%, 10%, 20%, 30%, 40%. Scanning Kelvin probe (SKP) technique was used to measure the potential distribution of the surface. The results showed that the impedance of the austenite declined with the increase of the strain and declined sharply under the strain of 30%. Potential of austenite decreased non-monotonously with increase of the strain. The potential reached the minimum under strain of 30% and then increased. Through the transmission electron microscope (TEM) results, plane dislocation pile-ups were observed in the grain boundary under the strain of 30% and transformed to cellular substructure structure and cell wall under 40%. Combined with the results of local electrochemistry impedance spectroscopy (LEIS) and surface potential, it may be concluded that it was the dislocation density and dislocation structure influence the impedance spectroscopy significantly, while surface potential was sensitive to the dislocation structure.