A carrier velocity model for electrical detection of gas molecules

• Ali Hosseingholi Pourasl,
• Sharifah Hafizah Syed Ariffin,
• Mohammad Taghi Ahmadi,
• Razali Ismail and
• Niayesh Gharaei

Beilstein J. Nanotechnol. 2019, 10, 644–653, doi:10.3762/bjnano.10.64

• . Thus, the energy dispersion relation of AGNR is developed considering the molecular adsorption effect using a tight binding (TB) method. The carrier velocity is calculated based on the density of states (DOS) and carrier concentration (n) to obtain I–V characteristics and to monitor its variation in

• path forward to overcome the constraints of experimental approaches. The adsorption of gas molecules can modulate different electrical and physical properties of the GNRs, such as density of states (DOS), carrier concentration, carrier velocity, I–V characteristics, and energy band structure. On the

• theoretical studies have confirmed that the velocity of the electrons is a function of carrier concentration (n) and density of states (DOS). The electron’s velocity is directly proportional to the DOS at any instance. The carrier velocity in the AGNR can be obtained by the accumulative velocity of all the

Geometrical optimisation of core–shell nanowire arrays for enhanced absorption in thin crystalline silicon heterojunction solar cells

• Robin Vismara,
• Olindo Isabella,
• Andrea Ingenito,
• Fai Tong Si and
• Miro Zeman

Beilstein J. Nanotechnol. 2019, 10, 322–331, doi:10.3762/bjnano.10.31

• taking place in less material. The higher carrier concentration results in a performance closer to the radiative limit, which is evidenced by the higher IQE observed at both short and long wavelengths. On the other hand, the lower EQE in the spectral region of 450–950 nm can be ascribed to a higher

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• change in graphene resistance via altering the local carrier concentration. After that, a wave of research regarding graphene has been set off. The mass production of single-layered graphene is difficult. Another problem is that pristine graphene does not have a bandgap, which means it is not suitable

Contactless photomagnetoelectric investigations of 2D semiconductors

• Marian Nowak,
• Marcin Jesionek,
• Barbara Solecka,
• Piotr Szperlich,
• Piotr Duka and
• Anna Starczewska

Beilstein J. Nanotechnol. 2018, 9, 2741–2749, doi:10.3762/bjnano.9.256

• forces [10]. In the magnetic field, B, perpendicular to the photogenerated carrier concentration gradient, the diffusing electrons and holes are deflected in opposite directions. Their current flows in a third, mutually perpendicular direction. The PME response decreases with the increase of

• occasional holes and cracks. The presence of single-layer graphene was confirmed by Raman spectroscopy using an NTEGRA Spectra (NT-NDT) device with a wavelength of 532 nm. The carrier mobility μe = 1256(25) cm2V−1s−1 and sheet carrier concentration ne = 4.65(6)·1016 m−2 in the graphene were determined using

• electrostatically tunable carrier density. The charge carriers can change from electrons to holes with the application of an electrostatic gate. The switching takes place at the Dirac point, where the carriers have a minimum density. The gate voltage, Vg, induces a sheet carrier concentration approximated by [33

High-temperature magnetism and microstructure of a semiconducting ferromagnetic (GaSb)_1−x(MnSb)_x alloy

• Leonid N. Oveshnikov,
• Elena I. Nekhaeva,
• Alexey V. Kochura,
• Alexander B. Davydov,
• Mikhail A. Shakhov,
• Sergey F. Marenkin,
• Oleg A. Novodvorskii,
• Alexander P. Kuzmenko,
• Alexander L. Vasiliev,
• Boris A. Aronzon and
• Erkki Lahderanta

Beilstein J. Nanotechnol. 2018, 9, 2457–2465, doi:10.3762/bjnano.9.230

• only if inclusions are sufficiently large to establish a second electronic phase (metal-type) despite the impact of the surrounding GaSb matrix. The parameters of these barriers (e.g., the width) substantially depend on the charge distribution, i.e., they depend on the carrier concentration. It is

• antiferromagnetic interactions between carriers and Mn atoms. One major parameter of the interaction of holes with MnSb inclusions is the width of the Schottky barriers dbarrier, which decreases with increasing carrier concentration [9]. This picture correlates with the concentration dependence of the saturation

• magnetization Msat presented in Figure 2. This also agrees well with the data obtained for previously studied (GaSb)1−x(MnSb)x films (see Figure 5 in [12]). As it can be seen from these figures, Msat increases with carrier concentration and saturates above Np ≈ 1020 cm−3 at which dbarrier becomes comparable

Thickness-dependent photoelectrochemical properties of a semitransparent Co₃O₄ photocathode

• Malkeshkumar Patel and
• Joondong Kim

Beilstein J. Nanotechnol. 2018, 9, 2432–2442, doi:10.3762/bjnano.9.228

• Co3O4 samples. Mott–Schottky (MS) characteristics allow us to describe the type of conductivity, free carrier concentration, and flat-band potential (VFB) of the samples. Figure 5e shows the thickness-dependent MS characteristics (1/C2 as a function of V vs RHE) of the Co3O4 samples, obtained at an

• values of NA1, NA2, VFB1, and VFB2, which are also summarized in Table 1, where NA is the acceptor carrier concentration. Thickness-dependent parameters including the T, Eg, and NA values of the Co3O4 samples suggest that the enhanced photocurrent performance of the PEC cell containing a 170 nm thick

• the Co3O4/FTO samples. Here t, T, λ, Eg, VFB and NA are the thickness of the Co3O4 layer, transmittance, photon wavelength, band gap, flat-band potential, and acceptor carrier concentration, respectively. Supporting Information Supporting Information File 146: Additional experimental data

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• changes upon exposure to the target gas. The adsorption of gas molecules on the sensing layer leads to redox reactions by serving as an electron donor or acceptor which depends on the reductive or oxidative nature of the target gas compared to molecular oxygen. As the charge carrier concentration changes

• 10 ppm H2S compared with pure ZnO NFs with a response of 1.57 at 230 °C and response and recovery times of 18 s and 20 s, respectively [196]. Doping with multivalent ions (In3+, Al3+, Sn4+, etc.) may change the defect density and carrier concentration of a ZnO matrix [201][202][203][204]. A common

Phosphorus monolayer doping (MLD) of silicon on insulator (SOI) substrates

• Noel Kennedy,
• Ray Duffy,
• Luke Eaton,
• Dan O’Connell,
• Scott Monaghan,
• Shane Garvey,
• James Connolly,
• Chris Hatem,
• Justin D. Holmes and
• Brenda Long

Beilstein J. Nanotechnol. 2018, 9, 2106–2113, doi:10.3762/bjnano.9.199

• excess of 1 × 1019 cm−3 with minimal impact on surface quality. Hall effect data proved that reducing SOI dimensions from 66 to 13 nm lead to an increase in carrier concentration values due to the reduced volume available to the dopant for diffusion. Dopant trapping was found at both Si–SiO2 interfaces

• quality remains relatively smooth. These values are important for both further analysis and industrial applications of MLD on SOI. The carrier-concentration analysis techniques ECV and Hall effect measurement both require high-quality surfaces and substrates to provide accurate data. Furthermore, from an

• industrial point of view it is important that surface quality remains good to ensure reproducibility over large sample quantities. P-MLD processing was carried out on 66 nm SOI wafers through the methods outlined in the Experimental section. The active carrier concentration levels shown in Figure 4 approach

A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si_1−xGe_x and Si layers

• Richard Daubriac,
• Emmanuel Scheid,
• Hiba Rizk,
• Richard Monflier,
• Sylvain Joblot,
• Rémi Beneyton,
• Pablo Acosta Alba,
• Sébastien Kerdilès and
• Filadelfo Cristiano

Beilstein J. Nanotechnol. 2018, 9, 1926–1939, doi:10.3762/bjnano.9.184

• such a small resolution. Thanks to the use of an AFM tip, 2D scanning spreading resistance microscopy (SSRM) has been shown to achieve sub-nanometre resolution [11][12]. However, in this technique, the carrier concentration is inferred from a resistivity profile under the assumption that carrier

• concentration varies ideally with mobility, which is not always the case, especially when a part of the dopant is not electrically active [13]. For this reason, reliable mobility and concentration profiling based on scanning probe techniques require a combination of resistivity measurements by SSRM with carrier

• strongly distort the final carrier concentration and mobility profiles. In this paper, we present an enhanced differential Hall effect measurement method that allows to precisely determine the level of dopant activation close to the semiconductor surface for Si and SiGe. First, we detail the etching

Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

• Yuxing Liang,
• Shuaiqi Fan,
• Xuedong Chen and
• Yuantai Hu

Beilstein J. Nanotechnol. 2018, 9, 1917–1925, doi:10.3762/bjnano.9.183

• piezoelectric semiconducting structure is essentially nonlinear unless the induced fluctuation of carrier concentration is very small. In this paper, the nonlinear governing equation of carrier concentration was established by coupling both piezoelectric effect and semiconduction. A nonlinear carrier-drift

• power was analyzed in detail. The electrode size for the optimal performance of a ZnO nanowire generator was proposed. This analysis that couples electromechanical fields and carrier concentration as a whole has some referential significance to piezotronics. Keywords: carrier drift; crystallogrpahic c

• . studied the linear solutions of electromechanical quantities in a bent ZNW under the assumption of a small fluctuation of the carrier concentration [31]. Electric fields are proven to be independent of the axial position along the c-axis except near the end regions, and carrier motion/redistribution is

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• of P- or B-atoms has severe implications for future applications of conventional impurity doping of Si in sub-10 nm technology nodes. Keywords: atom probe tomography; doping; photoluminescence; silicon nanocrystals; transient transmission; Introduction The conductivity type and free carrier

• concentration of a semiconductor can be controlled via doping. Conventional impurity doping requires the incorporation of a suitable foreign atom on a lattice site and its ionization by thermal energy. Therefore, the energetic position of a dopant in the bandgap has to be close to the respective band edges. For

Artifacts in time-resolved Kelvin probe force microscopy

• Sascha Sadewasser,
• Nicoleta Nicoara and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2018, 9, 1272–1281, doi:10.3762/bjnano.9.119

• function [3][4][5]. (ii) The CPD can reflect spatial variations in the charge density [6][7][8], individual localized charges [9], or even partial charge densities within a single molecule [10][11]. Finally, (iii) doping type and charge-carrier concentration in semiconductors will control the position of

Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg_1−xCd_xTe

• Alexandra V. Galeeva,
• Alexey I. Artamkin,
• Alexey S. Kazakov,
• Sergey N. Danilov,
• Sergey A. Dvoretskiy,
• Nikolay N. Mikhailov,
• Ludmila I. Ryabova and
• Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 1035–1039, doi:10.3762/bjnano.9.96

• contrast to most of the 3D topological insulators, Hg1−xCdxTe solid solutions are characterized by relatively low free carrier concentration values in the bulk, and may be therefore considered as good candidates for a case study focused on determination of the topological state contribution to the charge

• incident photon flux N irrespectively of the wavelength. It is reasonable to assume therefore that the positive photoconductivity in these samples results from an increase in the free carrier concentration due to the photogeneration process with the constant quantum efficiency independently on the

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

• Abdulrahman Altin,
• Maciej Krzywiecki,
• Adnan Sarfraz,
• Cigdem Toparli,
• Claudius Laska,
• Philipp Kerger,
• Aleksandar Zeradjanin,
• Karl J. J. Mayrhofer,
• Michael Rohwerder and
• Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

• semiconductor than the defect-dominated thin film initially is, and transforms it towards an intrinsic semiconductor. Decrease in defect concentration decreases also charge carrier concentration, and consequently the oxide conductivity. This transformation hinders a continuous current flow across the interface

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• factors, including absorbed oxygen species (O2−, O−, and O2−), charge carrier concentration, and the defects and vacancies on the ZnO surfaces. The gas response performance can be improved by a charge transfer process through surface modification [3][5][6] and doping of catalytic materials [7][8][9]. The

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• against NIR [135]. The high carrier concentration (≈5.9 × 1022 cm−3) of Au and Ag enables their intense LSPR excitations in the visible region [136]. The resonance in both Au and Ag can be controlled, but their high resistive loss, earth rarity and high cost are all disadvantages which limit them from

• , the carrier concentration of aluminium-doped zinc oxide (AZO) can be shifted from 0.5 to 10 × 1020 cm–3 by varying the concentration of Al, thus contributing to the wide-range SPR (2200–880 nm) [144]. Despite the tunable plasmonic features of semiconductors, some plasmonic semiconductors are

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• mobility of about 6.3 × 1013 cm−3 and 75 cm2 V−1 s−1, respectively. When xylene vapor (as an electron donor) is exposed to the sensing device, it reduces the resistance of the device due an increase in the majority carrier concentration. The same process can be seen for methanol, acting as powerful

• electron-donor gas molecules. This increment in the electron carrier concentration can reduce the resistivity of the device. When the gas leaves the chamber, the molecules which transfer the charge from weak van der Waals interaction leave the MoS2 layer and the concentration of the carrier reduces, hence

• defect sites, respectively. These results demonstrate that both xylene and methanol transfer a fraction of a charge to MoS2, which lead to an increase in carrier concentration and reduction of sample resistance. Conclusion In summary, we demonstrated a facile and efficient hydrothermal synthesis of MoS2

Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy

• Alexey D. Bolshakov,
• Alexey M. Mozharov,
• Georgiy A. Sapunov,
• Igor V. Shtrom,
• Nickolay V. Sibirev,
• Vladimir V. Fedorov,
• Evgeniy V. Ubyivovk,
• Maria Tchernycheva,
• George E. Cirlin and
• Ivan S. Mukhin

Beilstein J. Nanotechnol. 2018, 9, 146–154, doi:10.3762/bjnano.9.17

• carrier concentration at the level of 3∙1018 cm−3. The PL spectrum of sample 12, which was grown under the highest doping flux in our experiment series, significantly differs from the PL spectra of other considered samples 1, 3, and 4. The position of the PL maximum is shifted towards higher energy and

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• Equation 1–Equation 3 the field-effect mobility and charge carrier concentration have been calculated for three Mg-doped GaAs nanowires and the results are summarized in Table 1. As can be seen in Table 1, all Mg-doped GaAs nanowires have p-type electrical conductivity with the free hole concentration

Study of the surface properties of ZnO nanocolumns used for thin-film solar cells

• Neda Neykova,
• Jiri Stuchlik,
• Karel Hruska,
• Ales Poruba,
• Zdenek Remes and
• Ognen Pop-Georgievski

Beilstein J. Nanotechnol. 2017, 8, 446–451, doi:10.3762/bjnano.8.48

• eV and the free-carrier absorption in the red and the infrared part of the spectrum below photon energies of 2 eV. The infrared optical absorption increases with hydrogen plasma treatment indicating the increase of the free-carrier concentration as described in the Drude model. The increase of the

• free-carrier concentration is reasonably expected to increase the electrical conductivity of the ZnO NCs. Nevertheless, precise measurement of electrical conductivity is a difficult task and we plan to approach it by direct measurement on individual ZnO nanocolumns. The major changes appear within

• absorptance (Figure 4). This observation strongly suggests that the O-plasma treatment does not have any detrimental effects on the free-carrier concentration in the ZnO NCs. Conclusion In this work, randomly arranged densely packed and preferentially perpendicularly oriented ZnO nanocolumn arrays were grown

Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature

• Tapas Ghosh and
• Biswarup Satpati

Beilstein J. Nanotechnol. 2017, 8, 425–433, doi:10.3762/bjnano.8.45

• higher theoretical photocurrent density [23]. The practical conversion efficiency for CuO is low, which may be due to its low carrier concentration [24]. Again, the p-type CuO–n-type Si heterojunction is applicable for solar cells due to their similar electron affinity [25]. The reported open circuit

Performance of natural-dye-sensitized solar cells by ZnO nanorod and nanowall enhanced photoelectrodes

• Saif Saadaoui,
• Mohamed Aziz Ben Youssef,
• Moufida Ben Karoui,
• Rached Gharbi,
• Emanuele Smecca,
• Vincenzina Strano,
• Salvo Mirabella,
• Alessandra Alberti and
• Rosaria A. Puglisi

Beilstein J. Nanotechnol. 2017, 8, 287–295, doi:10.3762/bjnano.8.31

• ionization, which decreased the volume of Zn interstitials, resulting in a decrease of the carrier concentration [29]. Therefore, by comparing the two used sensitizers, under the same thermal conditions (200 °C) and at the same growth time (90 minutes), we noticed that the electrical performance was almost

Impact of contact resistance on the electrical properties of MoS₂ transistors at practical operating temperatures

• Filippo Giannazzo,
• Gabriele Fisichella,
• Aurora Piazza,
• Salvatore Di Franco,
• Giuseppe Greco,
• Simonpietro Agnello and
• Fabrizio Roccaforte

Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28

• function of the gate material (4.05 eV for the n+-doped Si back gate in our transistor), χ is the semiconductor electron affinity (4.2 eV for MoS2), ND is the semiconductor doping concentration (on the order of 1016 cm−3 in unintentionally doped MoS2) and ni is the intrinsic carrier concentration (for MoS2

Nitrogen-doped twisted graphene grown on copper by atmospheric pressure CVD from a decane precursor

• Ivan V. Komissarov,
• Nikolai G. Kovalchuk,
• Vladimir A. Labunov,
• Ksenia V. Girel,
• Olga V. Korolik,
• Mikhail S. Tivanov,
• Algirdas Lazauskas,
• Mindaugas Andrulevičius,
• Tomas Tamulevičius,
• Viktoras Grigaliūnas,
• Šarunas Meškinis,
• Sigitas Tamulevičius and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2017, 8, 145–158, doi:10.3762/bjnano.8.15

• ≈1590 cm−1 (Figure 7a) and ≈1585 cm−1 (Figure 8c), respectively. The maxima of the I2D/IG ratio are centered at ≈1 (Figure 7e) and ≈1.2 (Figure 8e) for samples A and B, respectively. Both of these facts indicate that sample A has a higher carrier concentration with respect to sample B [27][31

• information about structural and electrical properties of graphene. For example, the analysis of the line shape of the 2D band along with its spectral position can provide important information about the number of layers in graphene and the interlayer interaction [26]. From the G-band position, the carrier

• concentration can be obtained with high accuracy [27]. Finally, the analysis of the ID/IG ratio is becoming a common method for the point defect concentration evaluation [28][29]. From Raman spectroscopy results presented in the current research it was found that a non-monotonic distribution was inherent for

Obtaining and doping of InAs-QD/GaAs(001) nanostructures by ion beam sputtering

• Sergei N. Chebotarev,
• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Elena N. Zhivotova,
• Georgy A. Erimeev and
• Marina L. Lunina

Beilstein J. Nanotechnol. 2017, 8, 12–20, doi:10.3762/bjnano.8.2

• of impurities is observed throughout the layer. The increase in the evaporator temperature to 350 °С (RGaAs/SnTe ≈ 102) allowed us to reach an average carrier concentration of 2.1·1017 cm−3. In the doping profile that was obtained at an evaporator temperature of 400 °C (RGaAs/SnTe ≈ 101) an increase