TY - JOUR TI - A study of dopant incorporation in Te-doped GaAsSb nanowires using a combination of XPS/UPS, and C-AFM/SKPM AU - Ramaswamy, Priyanka AU - Devkota, Shisir AU - Pokharel, Rabin AU - Nalamati, Surya AU - Stevie, Fred AU - Jones, Keith AU - Reynolds, Lew AU - Iyer, Shanthi T2 - SCIENTIFIC REPORTS AB - Abstract We report the first study on doping assessment in Te-doped GaAsSb nanowires (NWs) with variation in Gallium Telluride (GaTe) cell temperature, using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), conductive-atomic force microscopy (C-AFM), and scanning Kelvin probe microscopy (SKPM). The NWs were grown using Ga-assisted molecular beam epitaxy with a GaTe captive source as the dopant cell. Te-incorporation in the NWs was associated with a positive shift in the binding energy of the 3d shells of the core constituent elements in doped NWs in the XPS spectra, a lowering of the work function in doped NWs relative to undoped ones from UPS spectra, a significantly higher photoresponse in C-AFM and an increase in surface potential of doped NWs observed in SKPM relative to undoped ones. The carrier concentration of Te-doped GaAsSb NWs determined from UPS spectra are found to be consistent with the values obtained from simulated I–V characteristics. Thus, these surface analytical tools, XPS/UPS and C-AFM/SKPM, that do not require any sample preparation are found to be powerful characterization techniques to analyze the dopant incorporation and carrier density in homogeneously doped NWs. DA - 2021/4/15/ PY - 2021/4/15/ DO - 10.1038/s41598-021-87825-4 VL - 11 IS - 1 SP - SN - 2045-2322 ER - TY - JOUR TI - Advances in secondary ion mass spectrometry for N-doped niobium AU - Angle, Jonathan W. AU - Palczewski, Ari D. AU - Reece, Charles E. AU - Stevie, Fred A. AU - Kelley, Michael J. T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B AB - Accurate secondary ion mass spectroscopy measurement of nitrogen in niobium relies on the use of closely equivalent standards, made by ion implantation, to convert nitrogen signal intensity to nitrogen content by determination of relative sensitivity factors (RSFs). Accurate RSF values for ppm-range nitrogen contents are increasingly critical, as more precision is sought in processes for next-generation superconducting radiofrequency (SRF) accelerator cavities. Factors influencing RSF value measurements were investigated with the aim of reliably attaining better than 10% accuracy in nitrogen concentrations at various depths into the bulk. This has been accomplished for materials typical of SRF cavities at the cost of increased attention to all aspects. DA - 2021/3// PY - 2021/3// DO - 10.1116/6.0000848 VL - 39 IS - 2 SP - SN - 2166-2754 ER - TY - JOUR TI - Influence of oxygen source on the ferroelectric properties of ALD grown Hf1-xZrxO2 films AU - Alcala, Ruben AU - Richter, Claudia AU - Materano, Monica AU - Lomenzo, Patrick D. AU - Zhou, Chuanzhen AU - Jones, Jacob L. AU - Mikolajick, Thomas AU - Schroeder, Uwe T2 - JOURNAL OF PHYSICS D-APPLIED PHYSICS AB - Hafnium oxide (HfO2), zirconium oxide (ZrO2), and the solid-solution (Hf1-xZrxO2) system continue to be some of the most relevant ferroelectric materials, in particular, for their promising application in CMOS integrated ferroelectric memories. Recent understanding of the influence of oxygen supplied during film deposition on the structural phase formation process in Hf1-xZrxO2 films has drawn attention to a commonly overlooked parameter for tuning ferroelectric and electrical properties of these films. In this paper, a comparison of O3 and O2 plasma used as the oxygen source in an atomic layer deposition process for Hf1-xZrxO2 films within the full compositional range is discussed. A combination of structural and electrical characterization methods grant insight on the influence of each of the oxygen sources on the crystalline phase formation during deposition of Hf1-xZrxO2 films. These observations are then correlated to the material's behavior regarding its ferroelectric and electrical properties; mainly, dielectric constant, ferroelectric remanent polarization, and number of electric field cycles to breakdown. DA - 2021/1/21/ PY - 2021/1/21/ DO - 10.1088/1361-6463/abbc98 VL - 54 IS - 3 SP - SN - 1361-6463 KW - ALD KW - PEALD KW - hafnium oxide KW - zirconium oxide KW - ferroelectric KW - ozone KW - oxygen plasma ER -