@article{pokharel_kuchoor_parakh_devkota_dawkins_ramaswamy_li_winkler_reynolds_iyer_2023, title={GaAs/GaAsSb Core-Shell Configured Nanowire-Based Avalanche Photodiodes up to 1.3?m Light Detection}, ISSN={["2574-0970"]}, DOI={10.1021/acsanm.2c03644}, abstractNote={We report the first study on a GaAs/GaAsSb core–shell (CS)-configured nanowire (NW)-based separate absorption, charge control, and multiplication region avalanche photodiode (APD) operating in the near-infrared (NIR) region. Heterostructure NWs consisted of GaAs and tunable band gap GaAs1–xSbx serving as the multiplication and absorption layers, respectively. A doping compensation of absorber material to boost material absorption, segment-wise annealing to suppress trap-assisted tunneling, and an intrinsic i-type and n-type combination of the hybrid axial core to suppress axial electric field are successfully adopted in this work to realize a room-temperature (RT) avalanche photodetection extending up to 1.3 μm. In an APD device operating at RT with a unity-gain responsivity of 0.2–0.25 A/W at ∼5 V, the peak gain of 160 @ 1064 nm and 18 V reverse bias, gain >50 @ 1.3 μm, are demonstrated. Thus, this work provides a foundation and prospects for exploiting greater freedom in NW photodiode design using hybrid axial and CS heterostructures.}, journal={ACS APPLIED NANO MATERIALS}, author={Pokharel, Rabin and Kuchoor, Hirandeep and Parakh, Mehul and Devkota, Shisir and Dawkins, Kendall and Ramaswamy, Priyanka and Li, Jia and Winkler, Christopher and Reynolds, Lew and Iyer, S.}, year={2023}, month={Mar} }
 @article{ovalle_rock_winkler_hartshorn_barr_cullom_tarafder_prost_white_anderson_et al._2023, title={Microstructure development and properties of micro-alloyed copper, Cu-0.3Zr-0.15Ag, produced by electron beam additive manufacturing}, volume={197}, ISSN={1044-5803}, url={http://dx.doi.org/10.1016/j.matchar.2023.112675}, DOI={10.1016/j.matchar.2023.112675}, abstractNote={A micro-alloyed copper powder, Cu-0.3Zr-0.15Ag wt%, was produced using gas atomization reaction synthesis. Zirconium was added to copper to sequester the oxygen present as copper oxide surface films on the powder particles. The as-received powders, as well as the intentionally oxidized powders were used to fabricate solid test articles by electron beam powder bed fusion additive manufacturing. Dense samples fabricated from as-received powder demonstrated nominal UTS, yield, and elongation values at 260 MPa, 150 MPa, and 34%, respectively. The average electrical conductivity of these samples was measured at 95% of the international annealed copper standard (IACS). Samples fabricated from the oxidized powder exhibited nominal UTS, yield, and elongation of 241 MPa, 146 MPa, and 43%, respectively, with an electrical conductivity of 95% IACS. During characterization, it was observed that, rather than forming nano-scale dispersoids, the Zirconia (ZrO2) appeared as discontinuous stringers in the metallographic cross-sections that crossed grain and melt pool boundaries. This was rationalized by tracing the presence of the micro-alloying addition of elemental zirconium, which was found to react with surface oxides dissociated in the melt pool to form ZrO2, which then solidified on the surface of the melt pool through an allotropic transformation to monoclinic ZrO2 in discontinuous films and spheroids ranging in size from nanometers to microns. This was confirmed by microscopic analysis of the tops of the melt pools. On subsequent melt passes, these ZrO2 structures were displaced and redistributed within the melt pool.}, journal={Materials Characterization}, publisher={Elsevier BV}, author={Ovalle, Denysse Gonzalez and Rock, Christopher and Winkler, Christopher and Hartshorn, Devin and Barr, Chris and Cullom, Tristan and Tarafder, Prithwish and Prost, Tim and White, Emma and Anderson, Iver and et al.}, year={2023}, month={Mar}, pages={112675} }
 @article{chan_auguste_romanovskaia_morales_schmidt_romanovski_winkler_qiu_wang_kaoumi_et al._2023, title={Multi-length scale characterization of point defects in thermally oxidized, proton irradiated iron oxides}, volume={28}, ISSN={["2589-1529"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85152241647&partnerID=MN8TOARS}, DOI={10.1016/j.mtla.2023.101762}, abstractNote={A key for the success of safe nuclear power generation system is to consider structural materials that are economical, meet mechanical property needs, possess good corrosion resistance, and are radiation tolerant. Nevertheless, fundamental insights that elucidate the details of radiation damage on materials corrosion performance are lacking. This includes the behavior of surface oxides which often regulate corrosion. For example, it is unclear how non-equilibrium point defects, oxide structure, mass transport in oxides, and subsequent oxidation behavior are altered by the radiation. In this work, some of the effects of proton irradiation on the attributes of point defects, iron oxide microstructures, and the physical nature of the oxidation product were correlated with corrosion behavior. Iron oxides, fabricated by thermal oxidation in air at 400°C and 800°C for 1 h, were subjected to 200 keV, 0.03 dpa (displacements per atom) of proton irradiation, and subjected to corrosion reactivity assessment using AC and DC electrochemical methods. Experimental methods that target materials information at different length scales, such as positron annihilation spectroscopy (atomistic), transmission electron microscopy (mesoscopic), and electrochemical methods (macroscopic), were coupled to shed light on the impact of radiation-induced defect modifications and structural changes in oxides on corrosion reactivity which ultimately affects durability in harsh environments.}, journal={MATERIALIA}, author={Chan, Ho Lun and Auguste, Rasheed and Romanovskaia, Elena and Morales, Angelica Lopez and Schmidt, Franziska and Romanovski, Valentin and Winkler, Christopher and Qiu, Jie and Wang, Yongqiang and Kaoumi, Djamel and et al.}, year={2023}, month={May} }
 @article{chan_auguste_romanovskaia_morales_liedke_schmidt_butterling_romanovski_winkler_qiu_et al._2023, title={Multi-length scale characterization of point defects in thermally oxidized, proton irradiated iron oxides (vol 28, 101762, 2023)}, volume={31}, ISSN={["2589-1529"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85168466212&partnerID=MN8TOARS}, DOI={10.1016/j.mtla.2023.101868}, journal={MATERIALIA}, author={Chan, Ho Lun and Auguste, Rasheed and Romanovskaia, Elena and Morales, Angelica Lopez and Liedke, Maciej Oskar and Schmidt, Franziska and Butterling, Maik and Romanovski, Valentin and Winkler, Christopher and Qiu, Jie and et al.}, year={2023}, month={Sep} }
 @article{christudasjustus_felde_witharamage_esquivel_darwish_winkler_gupta_2023, title={Age-hardening behavior, corrosion mechanisms, and passive film structure of nanocrystalline Al-V supersaturated solid solution}, volume={135}, ISSN={["1941-1162"]}, url={https://doi.org/10.1016/j.jmst.2022.06.044}, DOI={10.1016/j.jmst.2022.06.044}, abstractNote={The effect of age-hardening on microstructure, hardness, and corrosion of an Al-5at.%V alloy, produced using high-energy ball milling and subsequent cold compaction, has been investigated. The alloy exhibited a grain size below 100 nm and extremely high solid solubility of V in Al (3.1 at.%). The age-hardening was carried out at 150, 200, and 250 °C. The peak-aged condition of 150 °C demonstrated the highest hardness—transpired from grain refinement, precipitation, and solid solution hardening. The corrosion resistance of the Al-5at.%V alloy was studied as a function of aging conditions. The peak-aged condition retained the corrosion resistance while it deteriorated in the over-aged condition. Nonetheless, the corrosion resistance of the ball-milled Al alloys in all the aging conditions was superior to that of pure Al. The passive film structure and origin of corrosion were studied using scanning/transmission electron microscopy (S/TEM). The high corrosion resistance of the alloy was attributed to the V enrichment at the film/metal interface and deposition of V on the cathodic phases, which suppresses the dissolution of Al within the pit and therefore promotes repassivation in the early stages of corrosion.}, journal={JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY}, author={Christudasjustus, J. and Felde, M. R. and Witharamage, C. S. and Esquivel, J. and Darwish, A. . A. . and Winkler, C. and Gupta, R. K.}, year={2023}, month={Feb}, pages={1–12} }
 @article{hower_berti_winkler_qian_briot_2022, title={High-Resolution Transmission Electron Microscopy Study of a Powder River Basin Coal-Derived Fly Ash}, volume={12}, ISSN={["2075-163X"]}, DOI={10.3390/min12080975}, abstractNote={Examination of a fly ash derived from the combustion of a low-S, subbituminous Powder River Basin coal by Scanning Electron Microscopy (SEM) and High-resolution Transmission Electron Microscopy (HRTEM), both supplemented by Energy-dispersive X-ray spectroscopy (EDS), showed that the fly ashes were dominated by amorphous phases, Ca-rich plagioclase feldspars, Mg-rich phases, complex Ca-Mg-Al-Si-Ti-Fe grains, and trace amounts of REE-rich particles. Many of the particles were rimmed by a Ca-S, possibly a sulfate. HRTEM-EDS examination of a REE-rich particle proved it to be a mix of light- and heavy-rare earth minerals mixed with amorphous phases.}, number={8}, journal={MINERALS}, author={Hower, James C. and Berti, Debora and Winkler, Christopher R. and Qian, Dali and Briot, Nicolas J.}, year={2022}, month={Aug} }