Discovery of Rubidium, Strontium, Molybdenum, and Rhodium Isotopes

Currently, thirty-one rubidium, thirty-five strontium, thirty-five molybdenum and thirty-eight rhodium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: To be published in Atomic Data and Nuclear Data Table

Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes

Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine tellurium, thirty-eight iodine, and forty xenon isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: to be published in At. Data Nucl. Data Table

Polarity in GaN and ZnO: Theory, measurement, growth, and devices

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Rev. 3, 041303 (2016) and may be found at https://doi.org/10.1063/1.4963919.The polar nature of the wurtzite crystalline structure of GaN and ZnO results in the existence of a spontaneous electric polarization within these materials and their associated alloys (Ga,Al,In)N and (Zn,Mg,Cd)O. The polarity has also important consequences on the stability of the different crystallographic surfaces, and this becomes especially important when considering epitaxial growth. Furthermore, the internal polarization fields may adversely affect the properties of optoelectronic devices but is also used as a potential advantage for advanced electronic devices. In this article, polarity-related issues in GaN and ZnO are reviewed, going from theoretical considerations to electronic and optoelectronic devices, through thin film, and nanostructure growth. The necessary theoretical background is first introduced and the stability of the cation and anion polarity surfaces is discussed. For assessing the polarity, one has to make use of specific characterization methods, which are described in detail. Subsequently, the nucleation and growth mechanisms of thin films and nanostructures, including nanowires, are presented, reviewing the specific growth conditions that allow controlling the polarity of such objects. Eventually, the demonstrated and/or expected effects of polarity on the properties and performances of optoelectronic and electronic devices are reported. The present review is intended to yield an in-depth view of some of the hot topics related to polarity in GaN and ZnO, a fast growing subject over the last decade

Discovery of Yttrium, Zirconium, Niobium, Technetium, and Ruthenium Isotopes

Currently, thirty-four yttrium, thirty-five zirconium, thirty-four niobium, thirty-five technetium, and thirty-eight ruthenium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: To be published in Atomic Data and Nuclear Data Table

Discovery of Cesium, Lanthanum, Praseodymium and Promethium Isotopes

Currently, forty-one cesium, thirty-five lanthanum, thirty-two praseodymium, and thirty-one promethium, isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.Comment: To be published in At. Data. Nucl. Data Table

Structural characterization of the -111- surfaces of CdZnTe and HgCdTe epilayers by x-ray photoelectron diffraction.

HgCdTe epilayers and lattice matched CdZnTe (111) substrates have been investigated by x-ray photoelectron diffraction to characterize their surface structure in regard to termination, reconstruction and relaxation as well as in regard to degradations. Well-ordered CdZnTe surfaces of stoichiometric composition were realized by Ar ion sputtering, while sputter cleaning of the HgCdTe epilayers led to a significant increase of the CdTe mole fraction in the surface region. However, the crystallinity of the HgCdTe surfaces is found to be maintained in spite of their compositional degradation. Ordered and nondegraded HgCdTe(111) surfaces are obtained by electrochemical etching. The examined (111) A and (111) B surfaces can be easily differentiated since their photoelectron diffraction patterns indicates a surprisingly perfect termination. Evidence for any reconstruction or relaxation of the investigated (111) surfaces of CdZnTe and HgCdTe is not found

Angle-resolved x-ray photoelectron spectroscopy as a noninvasive characterization technique for the surface region of processed -Hg, Cd-Te

The potential of angle-resolved x-ray photoelectron spectroscopy (ARXPS) for characterizing the surface region of processed compound semiconductor materials is explored with respect to depth-compositional profiling and with respect to assessing the crystalline surface structure. It is demonstrated by analyzing the sputtered surface region of a (Hg, Cd) Te wafer that ARXPS can readily distinguish between three different compositional zones regarding their sequence and their chemical nature in a depth region of about 50 A. The quantitative scaling of the depth profile is accomplished using a theoretical model of photoemission from a planar sample covered with two uniform overlayer. It is futher demonstrated, by analyzing a (Hg Cd) Te sample grown by liquid phase epitaxy on (111) oriented (Cd, Zn) Te, that azimuthal and polar variation in the angle-resolved photoemission of Hg, Cd and Te occur which are indicative of the phenomenon of x-ray photoelectron diffraction (XPD). The prominent m axima of the respective photoemissions were observed at three azimuthal angles (120 degree C periodicity) for a polar angle of about 35 degree C. A shift of 60 degree C betweeen the azimuthal maxima of the photoemission of Te and the metal atoms (Cd or Hg) is attributed to a reconstruction of the examined (111) surface