<i>Photoconductivity of Solids</i>

Bube, Richard H.; Rice, Stuart A.

doi:10.1063/1.3057560

Cited by 404 publications

(123 citation statements)

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“…The capture cross-section of a level determines its ability to capture and re-emit the carriers. 18 Consequently the effect of these levels on the conduction mechanism is more evident than in the rhombohedral phase. The present study indicates that the conductivity of strained BFO is dependent on the history of the sample, particularly if the sample has been or not illuminated with above-band gap light.…”

Section: Discussionmentioning

confidence: 99%

“…As a result, the decay time of the conductivity is largely enhanced and is much higher than the usual lifetime of charge carriers. [17][18][19] We assume that the origin of the persistent photoconductivity is a level or a distribution of levels that exist within the band gap of BFO, and are in proximity of the mobility edge.…”

Section: Persistent Photoconductivitymentioning

confidence: 99%

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Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films

et al. 2014

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A drastic change in the conductivity of strained BiFeO 3 (BFO) films is observed after illuminating them with above-band gap light. This has been termed as persistent photoconductivity. The enhanced conductivity decays exponentially with time. A trapping character of the sub-band levels and their subsequent gradual emptying is proposed as a possible mechanism. KeywordsBiFeO 3 , strain, enhanced conductivity, persistent photoconductivity, thermally stimulated current Strained BiFeO 3 (BFO) has proven to show intriguing properties, many of which are very different from the parent non-strained BFO phase. BFO is generally known to have a

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Section: Discussionmentioning

confidence: 99%

Section: Persistent Photoconductivitymentioning

confidence: 99%

Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films

et al. 2014

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“…The plots indicate a linear increase of current in the dark and the visible light illuminated TiO 2 thin films in Fig.9. Photoconductivity study of TiO 2 thin films cases with an increase in applied field depicting the ohmic nature of the contacts 30 . It was observed that both the dark and the photo currents increased linearly with the applied electric field with the dark current being less than the photocurrent which is termed positive photoconductivity.…”

Section: Photoconductivity Studiesmentioning

confidence: 99%

Investigations on the Synthesis, Optical and Electrical Properties of TiO2 Thin Films by Chemical Bath Deposition (CBD) method

2016

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Titanium dioxide (TiO 2 ) thin films were prepared by Chemical Bath Deposition (CBD) method. The X-ray diffraction (XRD) analysis was used to examine the structure and to determine the crystallite size of TiO 2 thin film. The surface morphology of the film was studied using Scanning Electron Microscopy (SEM).The optical properties were studied using the UV-Visible and photoluminescence (PL) spectrum. Optical constants such as band gap, refractive index, extinction coefficient and electric susceptibility were determined. The FT-IR spectrum revealed the strong presence of TiO 2 . The dielectric properties of TiO 2 thin films were studied for different frequencies and different temperatures. The AC electrical conductivity test revealed that the conduction depended both on the frequency and the temperature. Photoconductivity study was carried out in order to ascertain the positive photoconductivity of the TiO 2 thin films.

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“…The solid line in Figure 3a is the best fit to the data obtained by eq 2, from which F 0 ) 3.2 × 10 6 s -1 and n ) 0.7 have been deduced. The photoconductive gain is defined as the ratio between the number of electrons collected per unit time and the number of absorbed photons per unit time (G ) N el /N ph ), 36 which can be derived from eq 2 by assuming η ) 1 for simplicity:…”

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confidence: 99%

ZnO Nanowire UV Photodetectors with High Internal Gain

et al. 2007

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ZnO nanowire (NW) visible-blind UV photodetectors with internal photoconductive gain as high as G ∼ 10 8 have been fabricated and characterized. The photoconduction mechanism in these devices has been elucidated by means of time-resolved measurements spanning a wide temporal domain, from 10 -9 to 10 2 s, revealing the coexistence of fast (τ ∼ 20 ns) and slow (τ ∼ 10 s) components of the carrier relaxation dynamics. The extremely high photoconductive gain is attributed to the presence of oxygen-related hole-trap states at the NW surface, which prevents charge-carrier recombination and prolongs the photocarrier lifetime, as evidenced by the sensitivity of the photocurrrent to ambient conditions. Surprisingly, this mechanism appears to be effective even at the shortest time scale investigated of t < 1 ns. Despite the slow relaxation time, the extremely high internal gain of ZnO NW photodetectors results in gain-bandwidth products (GB) higher than ∼10 GHz. The high gain and low power consumption of NW photodetectors promise a new generation of phototransistors for applications such as sensing, imaging, and intrachip optical interconnects.Because of its wide band gap (E g ) 3.4 eV), low cost, and ease of manufacturing, ZnO is emerging as a potential alternative to GaN in optoelectronic applications, 1 including light-emitting diodes, laser diodes, and photodetectors for the UV spectral range. In the past decade, the demonstration of a large variety of functional ZnO nanowire (NW) devices such as field effect transistors, 2,3 optically pumped lasers, 4,5 and chemical and biological sensors 6 have aroused growing interest in this material. 7 In particular, ZnO NW photodetectors and optical switches have been the subject of extensive investigations. [8][9][10][11][12][13][14][15][16][17][18] Despite the abundant research on NW photoconduction, 19 the two main factors contributing to the high photosensitivity of such nanostructures have been scarcely recognized: (1) the large surface-to-volume ratio and the presence of deep level surface trap states in NWs greatly prolongs the photocarrier lifetime; (2) the reduced dimensionality of the active area in NW devices shortens the carrier transit time. Indeed, the combination of long lifetime and short transit time of charge carriers can result in substantial photoconductive gain. [20][21][22] In this letter, we present ZnO NW photodetectors with large photoresponse; upon UV illumination at relatively low light intensities (I ∼ 10 µW/cm 2 ), the current in ZnO NWs increases by several orders of magnitude, which translates to a photoconductive gain of G > 10 8 . To elucidate the photoconduction mechanism that involves fast carrier thermalization and trapping at the NW surface and electronhole recombination at extended and localized states, we have studied the photoconductivity of ZnO NWs by time-resolved measurements and in different ambient conditions (e.g., in air or under vacuum). A physical model was developed to illustrate the origin of the photoconductive gain in ...

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Photoconductivity of Solids

Cited by 404 publications

References 0 publications

Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films

Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films

Investigations on the Synthesis, Optical and Electrical Properties of TiO2 Thin Films by Chemical Bath Deposition (CBD) method

ZnO Nanowire UV Photodetectors with High Internal Gain

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Photoconductivity of Solids

Cited by 404 publications

References 0 publications

Persistent Photoconductivity in Strained Epitaxial BiFeO3 Thin Films

Persistent Photoconductivity in Strained Epitaxial BiFeO3 Thin Films

Investigations on the Synthesis, Optical and Electrical Properties of TiO2 Thin Films by Chemical Bath Deposition (CBD) method

ZnO Nanowire UV Photodetectors with High Internal Gain

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Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films

Persistent Photoconductivity in Strained Epitaxial BiFeO₃ Thin Films