DC CONDUCTION MECHANISMS IN Al–SnO2–Al STRUCTURE DEPOSITED BY THERMAL EVAPORATION

2008 ◽  
Vol 15 (03) ◽  
pp. 207-216
Author(s):  
M. ANWAR ◽  
I. M. GHAURI ◽  
S. A. SIDDIQI ◽  
NAVEED AFZAL
Keyword(s):  
Electrical Conductivity ◽  
Substrate Temperature ◽  
Oxygen Vacancies ◽  
Annealing Temperature ◽  
Current Theory ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Valence States ◽  
Metal Insulator Metal ◽  
Main Barrier

The DC conduction mechanisms in metal–insulator–metal sandwich structure based on amorphous thin films of SnO 2 have been studied in the thickness range 100–400 nm, in the substrate temperature range 293–543 K, and in the annealing temperature range 473–773 K, and the results are discussed in terms of current theory. It is observed that at low field and low temperature the conduction mechanism is found to obey the hopping model, at higher temperature the conduction takes place by transport in the extended states but at high field the main barrier lowering effect is associated with localized centers. The increase in electrical conductivity with film thickness is caused by the oxygen vacancies and [Formula: see text] defects which generate carriers in the films. The increase in electrical conductivity due to an increase in substrate temperature is ascribed to the increasing concentration of ionized donors and hoping of electrons between metal ions in two different valence states. The formation of tin species of lower valence states and doubly ionized oxygen vacancies are thought to be responsible for the increase in electrical conductivity at higher annealing temperature.

scholarly journals Tuning the Electrical and Thermoelectric Properties of N Ion Implanted SrTiO3 Thin Films and Their Conduction Mechanisms

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anuradha Bhogra ◽  
Anha Masarrat ◽  
Ramcharan Meena ◽  
Dilruba Hasina ◽  
Manju Bala ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Temperature Regime ◽  
Electrical Transport ◽  
Ion Beam ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Band Conduction

Abstract The SrTiO3 thin films were fabricated by pulsed laser deposition. Subsequently ion implantation with 60 keV N ions at two different fluences 1 × 1016 and 5 × 1016 ions/cm2 and followed by annealing was carried out. Thin films were then characterized for electronic structure, morphology and transport properties. X-ray absorption spectroscopy reveals the local distortion of TiO6 octahedra and introduction of oxygen vacancies due to N implantation. The electrical and thermoelectric properties of these films were measured as a function of temperature to understand the conduction and scattering mechanisms. It is observed that the electrical conductivity and Seebeck coefficient (S) of these films are significantly enhanced for higher N ion fluence. The temperature dependent electrical resistivity has been analysed in the temperature range of 80–400 K, using various conduction mechanisms and fitted with band conduction, near neighbour hopping (NNH) and variable range hopping (VRH) models. It is revealed that the band conduction mechanism dominates at high temperature regime and in low temperature regime, there is a crossover between NNH and VRH. The S has been analysed using the relaxation time approximation model and dispersive transport mechanism in the temperature range of 300–400 K. Due to improvement in electrical conductivity and thermopower, the power factor is enhanced to 15 µWm−1 K−2 at 400 K at the higher ion fluence which is in the order of ten times higher as compared to the pristine films. This study suggests that ion beam can be used as an effective technique to selectively alter the electrical transport properties of oxide thermoelectric materials.

scholarly journals Electrical conductivity and conduction mechanisms in (Na0.5Bi0.5TiO3)1−x(BiScO3)x (0.00 ≤ x ≤ 0.25) solid solutions

2018 ◽  
Vol 6 (43) ◽  
pp. 11598-11607 ◽  
Author(s):  
F. Yang ◽  
P. Wu ◽  
D. C. Sinclair
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Oxygen Vacancies ◽  
Ion Conduction ◽  
Conduction Mechanisms ◽  
Oxide Ion Conduction ◽  
Oxide Ion

Large acceptor ions on B-sites are less effective in trapping oxygen vacancies and consequently less effective to suppress the oxide-ion conduction in NBT.

scholarly journals Suppression of electrical conductivity and switching of conduction mechanisms in ‘stoichiometric’ (Na0.5Bi0.5TiO3)1−x(BiAlO3)x (0 ≤ x ≤ 0.08) solid solutions

2017 ◽  
Vol 5 (29) ◽  
pp. 7243-7252 ◽  
Author(s):  
Fan Yang ◽  
Patrick Wu ◽  
Derek C. Sinclair
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Electrical Conduction ◽  
Oxygen Vacancies ◽  
Conduction Mechanism ◽  
Fine Tuning ◽  
Electrical Conduction Mechanism ◽  
Conduction Mechanisms

Fine-tuning the electrical conduction mechanism(s) of NBT-based materials by trapping oxygen vacancies using B-site acceptor dopants.

DC CONDUCTION MECHANISMS IN AMORPHOUS THIN FILMS OF MIXED OXIDES In2O3–SnO2 SYSTEM DEPOSITED BY CO-EVAPORATION

2006 ◽  
Vol 20 (15) ◽  
pp. 2159-2174 ◽  
Author(s):  
M. ANWAR ◽  
S. A. SIDDIQI ◽  
I. M. GHAURI
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Film Thickness ◽  
Substrate Temperature ◽  
Oxidation State ◽  
Dielectric Constants ◽  
Amorphous Thin Films ◽  
Conduction Mechanisms ◽  
Free Band ◽  
Band Conduction

A discussion of dc conduction mechanisms in thermally co-evaporated amorphous thin films of Al – In 2 O 3– SnO 2– Al structure is presented. Composition (in molar %), film thickness, substrate temperature, and post deposition annealing have profound effects on the electrical properties of the films. The effects of temperature on the I – V characteristics and electrical conductivity of Al – In 2 O 3– SnO 2– Al structure are also reported. The values of dielectric constants estimated by capacitance measurements suggest that high-field conduction mechanism is predominantly of Poole–Frenkel type. At low temperature and low field the electron hopping process dominates but at higher temperature the conduction takes place by transport in the extended states (free-band conduction). The transition from hopping to free band conduction is due to overlapping of localized levels and the free band. The increase in the formation of ionized donors with increase in temperature during electrical measurements indicates that electronic part of the conductivity is higher than the ionic part. The initial increase in conductivity with increase in Sn content in In 2 O 3 lattice is caused by the Sn atom substitution of In atom, giving out one extra electron. The decrease in electrical conductivity above the critical Sn content (10 mol % SnO 2) is caused by the defects formed by Sn atoms, which act as carrier traps rather than electron donors. The increase in electrical conductivity with film thickness is caused by the increase in free carriers density, which is generated by oxygen vacancy acting as two electrons donor. The increase in conductivity with substrate temperature and annealing is due either to the severe deficiency of oxygen, which deteriorates the film properties and reduces the mobility of the carriers or to the diffusion of Sn atoms from interstitial locations into the In cation sites and formation of indium species of lower valence state so that the In 3+ oxidation state may be changed to the In 2+ oxidation state.

Effects of Oxygen Vacancies and Cation Valence States on the Triboelectric Property of Substoichiometric Oxide Films

2021 ◽  
Author(s):  
Yongqiao Zhu ◽  
Shiquan Lin ◽  
Wenchao Gao ◽  
Miao Zhang ◽  
Chaogui Yang ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Oxide Films ◽  
Valence States

About the Electrical Activation of 1×1020 cm-3 Ion Implanted Al in 4H-SiC at Annealing Temperatures in the Range 1500 - 1950°C

2018 ◽  
Vol 924 ◽  
pp. 333-338 ◽  
Author(s):  
Roberta Nipoti ◽  
Alberto Carnera ◽  
Giovanni Alfieri ◽  
Lukas Kranz
Keyword(s):  
Activation Energy ◽  
Sheet Resistance ◽  
Annealing Time ◽  
Thermal Activation ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Activation Energy ◽  
Electrical Activation ◽  
Temperature Range ◽  
Annealing Temperatures

The electrical activation of 1×1020cm-3implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

scholarly journals Preparation and Thermoelectric Properties of Graphite/poly(3,4-ethyenedioxythiophene) Nanocomposites

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2849 ◽  
Author(s):  
Yong Du ◽  
Haixia Li ◽  
Xuechen Jia ◽  
Yunchen Dou ◽  
Jiayue Xu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Oxidative Polymerization ◽  
Polymerization Process ◽  
Measurement Temperature ◽  
Temperature Range ◽  
Different Content

Graphite/poly(3,4-ethyenedioxythiophene) (PEDOT) nanocomposites were prepared by an in-situ oxidative polymerization process. The electrical conductivity and Seebeck coefficient of the graphite/PEDOT nanocomposites with different content of graphite were measured in the temperature range from 300 K to 380 K. The results show that as the content of graphite increased from 0 to 37.2 wt %, the electrical conductivity of the nanocomposites increased sharply from 3.6 S/cm to 80.1 S/cm, while the Seebeck coefficient kept almost the same value (in the range between 12.0 μV/K to 15.1 μV/K) at 300 K, which lead to an increased power factor. The Seebeck coefficient of the nanocomposites increased from 300 K to 380 K, while the electrical conductivity did not substantially depend on the measurement temperature. As a result, a power factor of 3.2 μWm−1 K−2 at 380 K was obtained for the nanocomposites with 37.2 wt % graphite.

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