Crossover from Efros–Shklovskii variable range hopping to nearest-neighbor hopping in silicon nanocrystal random network

Inada, Mitsuru; Yamamoto, Hiroshi; Gibo, Manabu; Ueda, Rieko; Umezu, Ikurou; Tanaka, Shukichi; Saitoh, Tadashi; Sugimura, Akira

doi:10.7567/apex.8.105001

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…Due to this Coulomb gap between two interacting electrons, the density of states become nearly equal to zero near the Fermi level [40,41]. As a result, the logarithmic resistivity follows the linear dependency on T −1/2 (ES-VRH) instead of T −1/3 (Mott-VRH) [42,43]. Figures 6(c (ES-VRH).…”

Section: X-ray Photoelectron Spectroscopy and Origin Of Charge Transfermentioning

confidence: 96%

Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature

Debnath¹,

Bhattacharya²,

Saha³

2020

J. Phys. D: Appl. Phys.

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β-Co(OH)2 intrinsically is an antiferromagnetic semiconductor with Néel temperature (TN) of ~ 11 K. On the other hand, a semiconducting ferromagnet is indeed a very important component and used as ferromagnetic contacts in spin transistors. Therefore, realization of a 2D ferromagnetic semiconductor with higher Curie temperature and coercivity is a genuine challenge. In earlier work, we have used interface interaction to achieve a transition from antiferromagnetic to ferromagnetic ordering when the antiferromagnetic Ni(OH)2, Co(OH)2 are grown on the MoS2 surface acting as a 2D template. Thus interface interaction largely depends on the thickness of both the magnetic material as well as the template material. The major limitation of the earlier work is that we could not reduce the thickness of the template (MoS2), because of the limitation in the synthesis condition. Therefore, in the present work, we have used WS2 as a 2D template, the thickness of which is reduced to about 3–4 layers. As a consequence, a large enhancement in Curie temperature (131 K), coercivity (1285 Oe) and magnetoresistance (46 %) are observed in the present sample of the ultrathin β-Co(OH)2 phase grown on a thin-layered WS2 sheet.

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Section: X-ray Photoelectron Spectroscopy and Origin Of Charge Transfermentioning

confidence: 96%

Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature

Debnath¹,

Bhattacharya²,

Saha³

2020

J. Phys. D: Appl. Phys.

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“…Wienkes et al reported the transport property of phosphorus (P) doped amorphous/nanocrystalline silicon thin films and observed a crossover from Mott variable-range hopping (VRH) to multiphonon hopping (MPH) at about 50 K [20]. Inada et al observed a crossover from Efros-Shklovskii (E-S) VRH to nearest-neighbor hopping at 160 K in crystallized Si random network [21]. Additionally, Chen et al revealed the E-S VRH process of P-doped free-standing Si NCs in the temperature range of 80-300 K, and predicted the critical carrier concentration of metal-insulator transition (MIT) in Si NCs [22].…”

Section: Introductionmentioning

confidence: 99%

Experimental observations on metal-like carrier transport and Mott hopping conduction behaviours in boron-doped Si nanocrystal multilayers

Chen¹,

Li²,

Teng³

et al. 2023

Nanotechnology

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Studies on the carrier transport characteristics of semiconductor nanomaterials are the important and interesting issues which are helpful for developing the next generation of optoelectronic devices. In this work, we fabricate B-doped Si nanocrystals/SiO2 multilayers by plasma enhanced chemical vapor deposition with subsequent high temperature annealing. The electronic transport behaviors are studied via Hall measurements within wide temperature range (30-660 K). It is found that when the temperature is above 300 K, all the B-doped Si nanocrystals with the size of 4.0 nm exhibit the semiconductor-like conduction characteristics, while the conduction of Si nanocrystals with large size of 7.0 nm transforms from semiconductor-like to metal-like at high B-doping ratios. The critical carrier concentration of conduction transition can reach as high as 2.2×1020 cm-3, which is significantly higher than that of bulk counterpart and may be even higher for the smaller Si nanocrystals. Meanwhile, the Mott variable-range hopping dominates the carrier transport when the temperature is below 100 K. The localization radius of carriers can be regulated by the B-doping ratios and Si NCs size, which is contributed to the metallic insulator transition.

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“…Actually, the SAD may occur for different reasons. At high it could indicate the nearest neighbor hopping (NNH) [23,[34][35][36], or a band conductivity [6,37]. At low , however, the probability of both the NNH and band conductivity becomes negligibly small.…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Conductivity inn-Type Noncompensated Silicon below Insulator-Metal Transition

Danilyuk¹,

Trafimenko²,

Федотов³

et al. 2017

Advances in Condensed Matter Physics

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We investigate the transport properties ofn-type noncompensated silicon below the insulator-metal transition by measuring the electrical and magnetoresistances as a function of temperatureTfor the interval 2–300 K. Experimental data are analyzed taking into account possible simple activation and hopping mechanisms of the conductivity in the presence of two impurity bands, the upper and lower Hubbard bands (UHB and LHB, resp.). We demonstrate that the charge transport develops with decreasing temperature from the band edge activation (110–300 K) to the simple activation with much less energy associated with the activation motion in the UHB (28–90 K). Then, the Mott-type variable range hopping (VRH) with spin dependent hops occurs (5–20 K). Finally, the VRH in the presence of the hard gap (HG) between LHB and UHB (2–4 K) takes place. We propose the empiric expression for the lowTdensity of states which involves both the UHB and LHB and takes into account the crossover from the HG regime to the Mott-type VRH with increasing temperature. This allows us to fit the lowTexperimental data with high accuracy.

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Crossover from Efros–Shklovskii variable range hopping to nearest-neighbor hopping in silicon nanocrystal random network

Cited by 11 publications

References 22 publications

Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature

Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature

Experimental observations on metal-like carrier transport and Mott hopping conduction behaviours in boron-doped Si nanocrystal multilayers

Low Temperature Conductivity inn-Type Noncompensated Silicon below Insulator-Metal Transition

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Crossover from Efros–Shklovskii variable range hopping to nearest-neighbor hopping in silicon nanocrystal random network

Cited by 11 publications

References 22 publications

Transition from antiferromagnetic to ferromagnetic β-Co(OH)2 with higher Curie temperature

Transition from antiferromagnetic to ferromagnetic β-Co(OH)2 with higher Curie temperature

Experimental observations on metal-like carrier transport and Mott hopping conduction behaviours in boron-doped Si nanocrystal multilayers

Low Temperature Conductivity inn-Type Noncompensated Silicon below Insulator-Metal Transition

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Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature

Transition from antiferromagnetic to ferromagnetic β-Co(OH)₂ with higher Curie temperature