Negative and positive photoconductivity modulated by light wavelengths in carbon nanotube film

Zhu, Jia‐Lin; Zhang, Guowei; Wei, Jin; Sun, Jia‐Lin

doi:10.1063/1.4754624

Cited by 34 publications

(23 citation statements)

References 24 publications

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“…But in some unusual cases, conductivity decreases under illumination, even below the thermal equilibrium level, which is termed as negative photoconductivity (NPC). Although NPC is often considered as anomalous, there have been reports on NPC phenomenon for more than one century in a wide variety of materials such as Co-doped Si, [10] Se, [11] InAs, [12] Ag/Au nanoparticles, [13] γ-In 2 Se 3, [14] CNT, [15] and Bi-doped ZnSe. [16] However, there has been no consensus regarding the mechanism of NPC.…”

mentioning

confidence: 99%

Transition from Positive to Negative Photoconductance in Doped Hybrid Perovskite Semiconductors

Haque

Abdelhady

et al. 2019

Advanced Optical Materials

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Halide perovskites have been known to be photoconductive for more than half a century, and their efficient photocarrier generation gives rise to positive photoconductivity (PPC). In this work, we report the discovery of negative photoconductivity (NPC) in hybrid perovskite CH 3 NH 3 PbBr 3 after Bi doping. Transient photoconductivity measurements reveal a surprising bipolar behavior with a fast positive response followed by exponential negative photocurrent decay, resulting in an equilibrium photocurrent even below the dark level. The NPC effect in Bidoped CH 3 NH 3 PbBr 3 is among the largest ones reported so far for semiconductors. We propose that the transition to negative photoconductance is related to the presence of DX-like centers in Bi-doped halide perovskites, similar to doped III-V and chalcopyrite semiconductors. Such photogenerated DX-like centers in the Bi-doped CH 3 NH 3 PbBr 3 can trap mobile band electrons

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confidence: 99%

Transition from Positive to Negative Photoconductance in Doped Hybrid Perovskite Semiconductors

Haque

Abdelhady

et al. 2019

Advanced Optical Materials

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“…Slow processes also cause a well‐known persistent photoconductivity phenomenon. It was observed in a number of materials including carbon nanotube structures . Persistent photoconductivity of modified carbon nanotube film lasting for more than 30 min was reported by Khairoutdinov et al .…”

Section: Introductionmentioning

confidence: 70%

“…It was observed in a number of materials [16,17] including carbon nanotube structures. [18][19][20] Persistent photoconductivity of modified carbon nanotube film lasting for more than 30 min was reported by Khairoutdinov et al [19] The slow processes were attributed to the photoinduced electron transfer from attached molecular substituents to carbon nanotubes. Allen et al have demonstrated that the slow processes lasting for tens of minutes influence carrier mobility in a nanotube field-effect transistor.…”

Section: Introductionmentioning

confidence: 99%

Electronic and Ionic Electric Field Screening and Persistent Built‐In Electric Field in Carbon Nanotube/PCBM Films

Jašinskas

Oberndorfer

Hertel

et al. 2020

Physica Status Solidi (a)

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The application of carbon nanotubes in electronic devices requires detailed knowledge of their electrical properties. Herein, the long‐lasting electric field‐induced polarization of single‐wall carbon nanotube (SWCNT) networks is demonstrated. It is found that electric voltage applied to the films of SWCNTs and their blends with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) creates persistent polarization that partly screens the external electric field and creates a built‐in electric field of the opposite direction remaining for several days. The built‐in electric field has caused the appearance of an open‐circuit photovoltage and a short‐circuit photocurrent under the sample illumination at zero applied voltage. The built‐in field showed a clearly bicomponential decay. The short tens of microseconds component is attributed to the electronic polarization, while the long‐lived component, which decreases at low temperatures, is attributed to the temperature‐assisted motion of ions.

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“…28 However, the tunability of the dielectric properties of SWCNT in the THz range has not been reported yet, or is limited to DC characterization in the form of photocurrent measurements in response to optical and THz illumination. 29,30 In this paper, we experimentally investigate SWCNT layers under light illumination through a wide range of techniques and frequencies, with the aim to integrate them as tunable impedance surfaces for THz applications. The results presented here include: characterization with scanning electron microscopy (SEM), transmission electron microscopy (TEM), optical spectroscopy in the 200-2500 nm wavelength range, and Terahertz time domain spectroscopy (THz TDS) in the 0.2-1 THz frequency range.…”

Section: Introductionmentioning

confidence: 99%

Optically controlled dielectric properties of single-walled carbon nanotubes for terahertz wave applications

et al. 2018

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Materials with tunable dielectric properties are valuable for a wide range of electronic devices, but are often lossy at terahertz frequencies. Here we experimentally report the tuning of the dielectric properties of single-walled carbon nanotubes under light illumination. The effect is demonstrated by measurements of impedance variations at low frequency as well as complex dielectric constant variations in the wide frequency range of 0.1-1 THz by time domain spectroscopy. We show that the dielectric constant is significantly modified for varying light intensities. The effect is also practically applied to phase shifters based on dielectric rod waveguides, loaded with carbon nanotube layers. The carbon nanotubes are used as tunable impedance surface controlled by light illumination, in the frequency range of 75-500 GHz. These results suggest that the effect of dielectric constant tuning with light, accompanied by low transmission losses of the carbon nanotube layer in such an ultra-wide band, may open up new directions for the design and fabrication of novel Terahertz and optoelectronic devices.

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Negative and positive photoconductivity modulated by light wavelengths in carbon nanotube film

Cited by 34 publications

References 24 publications

Transition from Positive to Negative Photoconductance in Doped Hybrid Perovskite Semiconductors

Transition from Positive to Negative Photoconductance in Doped Hybrid Perovskite Semiconductors

Electronic and Ionic Electric Field Screening and Persistent Built‐In Electric Field in Carbon Nanotube/PCBM Films

Optically controlled dielectric properties of single-walled carbon nanotubes for terahertz wave applications

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