31. CVD Growth of Molybdenum Diselenide Surface Structures with Tailored MorphologyM. Naeem Sial, Usman Muhammad, Binjie Zheng, Yanan Yu, Andraž Mavrič, Fangzhu Qing, Matjaž Valant, Zhiming M. Wang, 2018, original scientific article Abstract: Controllable atmospheric pressure CVD has been optimized to grow transition metal dichalcogenide MoSe2 with tunable morphology at 750 °C on a silicon substrate with a native oxide layer of 250 nm. Utilizing tetrapotassium perylene-3,4,9,10-tetracarboxylate (PTAS) as a seed promoter and varying the vertical distance between the substrate and the precursor MoO3, different morphologies of MoSe2 were achieved, including 2D triangles, hexagons, 3D pyramids and vertically aligned MoSe2 sheets. We find that the shape of MoSe2 is highly dependent upon the distance h between the substrate and the precursor. The change in the morphology is attributed to the confinement of vapor (MoO3 and Se) precursors and their concentrations due to the change in h. These results are helpful in improving our understanding about the factors which influence the morphology (shape evolution) and also the continuous growth of MoSe2 films. Keywords: Transition metal dichalcogenides, 2D materials, Seed promotor, Chemical vapor deposition, Molybdenum diselenide Published in RUNG: 20.08.2018; Views: 3798; Downloads: 14 Full text (2,68 MB) |
32. Vertical profiling of aerosol properties with two-wavelength polarization Raman lidar over the Vipava valleyLonglong Wang, Samo Stamoč, Asta Gregorič, Griša Močnik, Luka Drinovec, Klemen Bergant, William Eichinger, 2018, published scientific conference contribution abstract Abstract: Presence of atmospheric aerosols affects the Earth’s radiation budget and thus also atmospheric thermal structure,
which in turn affects cloud and planetary boundary layer (PBL) dynamics. We combine in-situ and remote
measurements to determine aerosol properties in a representative hot-spot for air pollution in a complex terrain
configuration. Vertical profiles of aerosol properties were investigated using a two-wavelength polarization
Raman lidar system in the Vipava valley. Using lidar-obtained particle depolarization ratio, lidar ratio and
backscatter Ångström exponent (355 nm / 1064 nm), which depend on aerosol shape, size and refractive index,
thus the aerosols can be identified and the roles of different aerosol types in the observed atmospheric processes
were investigated. In addition, aerosol absorption coefficients were measured in-situ by Aethalometers (AE33,
Magee Scientific / Aerosol d.o.o.) on the valley floor and on the adjacent mountain range, 850 m above the lidar site.
Our primary goal was to study the variability of aerosol types within and above the Vipava valley, which
was performed using the entire lidar dataset from August – December 2017. Primary anthropogenic aerosols
within the valley is mainly emitted from two sources: individual domestic heating systems, which mostly use
biomass fuel and traffic. Natural aerosols, transported by long-range transport, such as mineral dust and sea salt,
were observed both above the PBL and entering into the PBL. Vertical distributions of aerosol properties, in par-
ticular the particle depolarization ratio, indicated atmospheric stratification with different aerosol types occupying
different height ranges. In the presence of Bora (strong down-slope wind), Kelvin-Helmholtz instabilities were
observed between the PBL and the free troposphere. Using aerosol type identification capability of our system,
we discovered that this instability was responsible for ejecting aerosols from the PBL up to 2 km into the free
troposphere.
In addition, we improved the reliability of aerosol identification in vertical profiles using absorption coeffi-
cient measured by Aethalometer. Combining it with the aerosol extinction coefficient at 355 nm derived from
lidar data, we derived aerosol single scattering albedo (SSA), which is an important parameter for aerosol
characterization. Keywords: Aerosol, Vipava valley, lidar Published in RUNG: 23.04.2018; Views: 4380; Downloads: 0 This document has many files! More... |
33. Distinguishing source specific black carbon production from meteorologically driven temporal variability by means of 222Rn tracerAsta Gregorič, Luka Drinovec, Irena Ježek, Janja Vaupotič, Longlong Wang, Maruška Mole, Samo Stanič, Griša Močnik, 2017, published scientific conference contribution abstract Keywords: black carbon, source apportionment, radon, planetary boundary layer, lidar Published in RUNG: 10.10.2017; Views: 5368; Downloads: 229 Full text (136,72 KB) |
34. Long-term investigation of aerosol variability in the boundary layer over Vipava valley based on lidar observations and black carbon measurementsLonglong Wang, Klemen Bergant, Marija Bervida, Luka Drinovec, William Eichinger, Asta Gregorič, Dafina Kikaj, Griša Močnik, Maruška Mole, Janja Vaupotič, Samo Stanič, 2017, published scientific conference contribution abstract Published in RUNG: 21.07.2017; Views: 5033; Downloads: 0 This document has many files! More... |
35. Electrical characteristics of the vertical GaN rectifiers fabricated on bulk GaN waferYaqi Wang, Hui Xu, Siddharth Alur, Yogesh Sharma, Fei Tong, Patrick Gartland, Tamara Issacs-Smith, Claude Ahyi, John Williams, Minseo Park, Ginger Wheeler, Mark Johnson, Andrew A. Allerman, Andrew Hanser, Tanya Paskova, Edward A. Preble, Keith R. Evans, 2011, original scientific article Keywords: GaN, rectifier Published in RUNG: 17.01.2017; Views: 4363; Downloads: 0 This document has many files! More... |
36. Growth of ZnO Nanorod Arrays on Flexible Substrates: Effect of Precursor Solution ConcentrationFei Tong, Kyusang Kim, Yaqi Wang, Resham Thapa, Yogesh Sharma, Aaron Modic, Ayayi Ahyi, Tamara Issacs-Smith, John Williams, Hosang Ahn, Hyejin Park, Dong-Joo Kim, Sungkoo Lee, Eunhee Lim, Kyeong K. Lee, Minseo Park, 2012, original scientific article Keywords: ZnO Nanorod Arrays, ITO-PET, solution growth Published in RUNG: 16.01.2017; Views: 4695; Downloads: 0 This document has many files! More... |
37. Ultra-low leakage and high breakdown Schottky diodes fabricated on free-standing GaN substrateYaqi Wang, Siddharth Alur, Yogesh Sharma, Fei Tong, Resham Thapa, Patrick Gartland, Tamara Issacs-Smith, Claude Ahyi, John Williams, Minseo Park, Mark Johnson, Tanya Paskova, Edward A Preble, Keith Evans, 2011, original scientific article Keywords: free-standing GaN substrate, Ultra-low leakage and high breakdown Schottky diodes Published in RUNG: 16.01.2017; Views: 4253; Downloads: 0 This document has many files! More... |
38. Lidar measurements of Bora wind effects on aerosol loadingMaruška Mole, Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Francisco Ocaña, Benedikt Strajnar, Primož Škraba, Marko Vučković, William Willis, 2017, original scientific article Abstract: The Vipava valley in Slovenia is well known for the appearance of strong, gusty North-East Bora winds, which occur as a result of air
flows over an adjacent orographic barrier. There are three revealing wind directions within the valley which were found to give rise to
specific types of atmospheric structures. These structures were investigated using a Mie scattering lidar operating at 1064 nm, which provided high temporal and spatial resolution backscatter data on aerosols, which were used as tracers for atmospheric flows. Wind
properties were monitored at the bottom of the valley and at the rim of the barrier using two ultrasonic anemometers. Twelve time periods between February and April 2015 were selected when lidar data was available. The periods were classified according to the wind speed and direction and investigated in terms of appearance of atmospheric structures. In two periods with strong or moderate Bora, periodic atmospheric structures in the lidar data were observed at heights above the mountain barrier and are believed to be Kelvin–Helmholtz waves, induced by wind shear. No temporal correlation was found between these structures and wind gusts at the ground level. The influence of the wind on the height of the planetary boundary layer was studied as well. In periods with low wind speeds, the vertical evolution of the planetary boundary layer was found to be governed
by solar radiation and clouds. In periods with strong or moderate Bora wind, convection within the planetary boundary layer was found to be much weaker due to strong turbulence close to the ground, which inhibited mixing through the entire layer. Keywords: Downslope wind
Lidar observations
Kelvin–Helmholtz waves
Bora Published in RUNG: 06.01.2017; Views: 5394; Downloads: 0 This document has many files! More... |
39. Application of the ultraviolet scanning elastic backscatter LiDAR for the investigation of aerosol variabilityFei Gao, Klemen Bergant, Samo Stanič, Longlong Wang, Ying Li, Songhui Li, Dengxin Hua, 2015, original scientific article Keywords: LIDAR, vertikalno pregledovanje, daljinsko zaznavanje, aerosoli, optične lastnosti Published in RUNG: 17.05.2016; Views: 6804; Downloads: 38 Link to full text |
40. Observations of atmospheric structures in the Vipava valley based on Lidar dataMaruška Mole, Longlong Wang, Samo Stanič, Asta Gregorič, Klemen Bergant, William Eichinger, Marko Vučković, 2016, published scientific conference contribution abstract Keywords: lidar, atmosferske strukture, vremenske razmere Published in RUNG: 03.05.2016; Views: 5054; Downloads: 0 This document has many files! More... |