Temperature and field dependent effective hole mobility and impact ionization at extremely high fields in amorphous selenium

Kabir, Md. Tanvir; Hijazi, Nour

doi:10.1063/1.4876239

Cited by 18 publications

(18 citation statements)

References 22 publications

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“…Figure 3 shows the effective hole mobility versus electric field at five different temperatures. The symbols, dotted, and solid lines represent the experimental data, previous model [12], and present model fit to the experimental data, respectively. The experimental data are extracted from Fig.…”

Section: Hole Mobility and Impact Ionizationmentioning

confidence: 99%

“…Therefore, neglecting the trap saturation effect, the shallow trap-controlled effective hole mobility h is given by [12] h (F, T) ϭ 0h (F, T)…”

Section: Effective Drift Mobilitymentioning

confidence: 99%

“…The effective drift mobility is believed to be shallow trap-controlled and thermally activated [11]. An analytical model for the electric field and temperaturedependent effective drift mobility of holes in a-Se was proposed in the literature [12]. However, the previous model underestimated the effective mobility at very high fields (higher than 60 V/m) especially at low temperatures.…”

Section: Introductionmentioning

confidence: 98%

“…Thus, there exists an optimum energy level from which the resultant escape probability is maximised. In this paper, the previous model [12] is extended by incorporating this escape probability and three-dimensional (3D) PF process. The modified models are fitted with the published experimental results on effective drift mobility of both holes and electrons with wide variations of applied electric fields and temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…The modified models are fitted with the published experimental results on effective drift mobility of both holes and electrons with wide variations of applied electric fields and temperatures. The present drift mobility model is incorporated into our recently proposed lucky-drift model [12], which is also applied to the electric field and temperature-dependent impact ionization coefficient of both holes and electrons in a-Se.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of temperature- and field-dependent effective drift mobilities and impact ionization coefficients in amorphous selenium

Hijazi

Kabir

2015

Can. J. Phys.

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The mechanisms of electric-field-and temperature-dependent effective drift mobility and impact ionization coefficient of both holes and electrons in amorphous selenium (a-Se) are investigated in this paper. An analytical model for the microscopic mobility, momentum relaxation mean free path, and hence the effective drift mobility and impact ionization coefficient of carriers, is proposed in this paper by considering the density of states distribution, field enhancement release rate from the shallow traps, and carrier heating. The results of the model are fitted with the published experimental results on effective mobility and impact ionization coefficient with wide variations of the applied electric field and temperature. A better fitting considering thermally activated tunneling for the field-enhancement release rate indicates that the effective drift mobility at extremely high fields is mainly controlled by the neutral defect states near the band edges. The density of state function near the band edges, consisting of an exponential tail and a Gaussian peak, can successfully describe the electric-fieldand temperature-dependent effective drift mobility characteristics in a-Se. The momentum relaxation mean free path decreases with increasing field and decreasing temperature, which is required to describe the electric-field-and temperature-dependent behaviors of impact ionization coefficient in a-Se. PACS Nos.: 72.20.Jv, 72.20.Ht, 71.23.An.Résumé : Nous étudions ici les mécanismes de dépendance en champs électriques et en température de la mobilité de dérive efficace et du coefficient d'ionisation par impact des trous et des électrons dans le sélénium amorphe (a-Se). Nous tenons compte de la distribution de densité d'états, de la libération du renforcement du champ des pièges peu profonds et du réchauffement des porteurs, afin de proposer un modèle analytique pour la mobilité microscopique, le libre parcours moyen de relaxation d'impulsion et ainsi la mobilité de dérive efficace et le coefficient d'ionisation par impact. Les résultats du modèle sont ajustés avec les résultats expérimentaux publiés sur la mobilité efficace et le coefficient d'ionisation par impact avec de grandes variations du champ électrique et de la température. Un meilleur ajustement qui tient compte d'un effet tunnel dans la libération de renforcement du champ indique que la mobilité de dérive aux valeurs élevées de champ est surtout contrôlée par les états défauts près des bords de bande. La fonction de densité d'états près du bord de bande qui consiste en un pic gaussien et une queue exponentielle peut décrire avec succès les caractéristiques de la dépendance sur le champ électrique et la température de la mobilité de dérive dans le a-Se. Le libre parcours moyen de relaxation de l'impulsion diminue lorsque le champ croît et que la température baisse, ce qui est nécessaire pour décrire correctement la dépendance en température du coefficient d'ionisation par impact dans a-Se. [Traduit par la Rédaction]

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Section: Hole Mobility and Impact Ionizationmentioning

confidence: 99%

“…Therefore, neglecting the trap saturation effect, the shallow trap-controlled effective hole mobility h is given by [12] h (F, T) ϭ 0h (F, T)…”

Section: Effective Drift Mobilitymentioning

confidence: 99%