The Poole-Frenkel Effect with Compensation Present

Yeargan, J. R.; Taylor, Howard L.

doi:10.1063/1.1656022

Cited by 406 publications

(200 citation statements)

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“…33 Considering the magnitude of the applied electric fields in the a-IGZO thin-film patches and the temperature dependence of the electrical conductance (Figures 3e and f), the conduction mechanisms based on tunneling can be neglected. 33 The P-F conduction is given as: 35,36 I PÀF pEexp 1…”

Section: Resultsmentioning

confidence: 99%

Structural-relaxation-driven electron doping of amorphous oxide semiconductors by increasing the concentration of oxygen vacancies in shallow-donor states

et al. 2016

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The electronic states of oxygen vacancies (V O s) in amorphous oxide semiconductors are shallow donors, deep donors or electron traps; these are determined by the local atomic structure. Because the amorphous phase is metastable compared with the crystalline phase, the degree of structural disorder is likely to decrease, which is referred to as structural relaxation (SR). Thus SR can affect the V O electronic state by changing the local atomic conditions. In this study, we demonstrated that electron doping is possible through the SR of amorphous oxides without redox reactions using a novel device structure that prevents extrinsic reactions with electrodes and ambient atmosphere during annealing. The concentration of V O s in the shallow-donor state in amorphous In-Ga-Zn-O (a-IGZO) increases from~10 16 to~10 19 cm − 3 with increasing annealing temperatures between 300 and 450°C. The SR-driven doping effect is strongly dependent on the annealing temperature but not on the annealing time. The Arrhenius activation energy of the SR-driven doping effect is 1.76 eV, which is similar to the bonding energies in a-IGZO. Our findings suggest that the free volume in a-IGZO decreases during SR, and the V O s in either deep-donor or electrontrap states are consequently transformed into shallow-donor states. NPG Asia Materials (2016) 8, e250; doi:10.1038/am.2016.11; published online 25 March 2016 INTRODUCTION Amorphous metal oxides, such as amorphous indium gallium zinc oxide (a-IGZO), have become mainstream materials for large-area and flexible electronics because the long-range structural disorder enhances the uniformity of the electrical properties and mechanical flexibility compared with crystalline metal oxides. 1-5 A notable characteristic of amorphous oxides, relative to their crystalline counterparts, is that these materials contain structural disorder-related defects (for example, free volume) in addition to non-stoichiometric defects (for example, oxygen vacancies), which significantly affect the corresponding electrical properties. 3,[6][7][8] Moreover, the degree of structural disorder in amorphous metal oxides is always likely to decrease to form more stable structures because internal atomic rearrangement occurs even below the glass transition temperature (T g ). This process is known as structural relaxation (SR) 9-11 and results in continuous changes in the electrical properties. Thus understanding the effects of SR on the electrical properties of amorphous oxides is important for applications in future electronics.In addition to uniformity and flexibility, amorphous metal oxides exhibit tunable electrical conductivity through redox reaction control

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Section: Resultsmentioning

confidence: 99%

Structural-relaxation-driven electron doping of amorphous oxide semiconductors by increasing the concentration of oxygen vacancies in shallow-donor states

et al. 2016

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“…The plot shows a linear behavior with appreciable deviation from linearity at lower electric field and at higher temperatures of 360 and 380 K. This is attributed to accumulation of space charge at the electrodes [18]. These data can be fitted to the relation [19]:…”

Section: I-v Characteristicsmentioning

confidence: 99%

Transient and Steady State Currents of Bisphenol A Corncobs Sample

Hanafy¹

2011

AMPC

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Transient current (I-t), current-voltage (I-V) characteristics, and dc conductivity ln(σ) for bisphenol A corncobs (BPACC) sample were investigated. At higher temperatures, I-V characteristics reveal that the dc current for the sample undergoes two regions one due to ohmic conduction and the other has been attributed to Space charge limited current (SCLC). The activation energy (E a ), the electron mobility (μ o ), effective electron mobility (μ e ), the concentration of the charge's concentrations in conduction band, trapping factor (θ) and the trap concentration (N t ) were calculated. At lower temperatures, the dc current exhibits a peculiar behavior for I-t regime and I-V characteristics. Transient current of BPACC sample exhibits approximately constant value at constant electric field and it has saturation value for I-V characteristics. The attained results suggest strongly the applicability of this material in the electrical applications.

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“…r is a degree of compensation whose value changes between 1 and 2 (1 ≤ r ≤ 2) [20,21], and it defines the effect of trapping or acceptor sensors. When r is equal to 1, then it is named as normal PF, while it corresponds to modified Poole-Frenkel effect or Poole-Frenkel with compensation when r = 2.…”

Section: Conduction Mechanismsmentioning

confidence: 99%

“…However, the analysis have strongly indicated that the conduction mechanism through the laser grown Ta 2 O 5 films in the applied voltage ranges is governed by the PF in the samples having a barrier height separating the traps from the conduction band. PF is based on the emission of trapped electrons toward the conduction band of the insulator [20,21]. Current density governed by the PF mechanism through the dielectric is given as [22];…”

Section: Conduction Mechanismsmentioning

confidence: 99%