Structural spectral response tuning in organic deep ultraviolet photodetectors

Zhu, Lu; Wang, Wen-Shuo; Yao, Zhigang; Zhang, Xiqing; Wang, Yongsheng

doi:10.1016/j.sse.2012.10.008

Cited by 17 publications

(5 citation statements)

References 31 publications

(47 reference statements)

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“…In the past two decades, the emergence of UV photodetectors based on wide‐bandgap (WBG) semiconductors has opened up an avenue to circumvent the above‐mentioned dilemma. The WBG semiconductors such as SiC, GaN, and some group II–V compounds, typically have bandgaps exceeding ≈3.10 eV, enabling room‐temperature detectors to possess fast response speed, and offering intrinsic visible‐blindness (response cutoff wavelength: ≈400 nm) . Moreover, these semiconductors generally possess significantly higher thermal conductivity than Si, which renders them suitable for operation in harsh environments (e.g., high temperature and high power).…”

Section: Introductionmentioning

confidence: 99%

Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

Xie

Tong

et al. 2019

Adv Funct Materials

356

243

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Due to its significant applications in many relevant fields, light detection in the solar-blind deep-ultraviolet (DUV) wavelength region is a subject of great interest for both scientific and industrial communities. The rapid advances in preparing high-quality ultrawide-bandgap (UWBG) semiconductors have enabled the realization of various high-performance DUV photodetectors (DUVPDs) with different geometries, which provide an avenue for circumventing numerous disadvantages in traditional DUV detectors. This article presents a comprehensive review of the applications of inorganic UWBG semiconductors for solar-blind DUV light detection in the past several decades. Different kinds of DUVPDs, which are based on varied UWBG semiconductors including Ga 2 O 3 , Mg x Zn 1−x O, III-nitride compounds (Al x Ga 1−x N/AlN and BN), diamond, etc., and operate on different working principles, are introduced and discussed systematically. Some emerging techniques to optimize device performance are addressed as well. Finally, the existing techniques are summarized and future challenges are proposed in order to shed light on development in this critical research field.with energy much higher than the semiconductor bandgap. Moreover, due to light absorption by the surface passivation layers, typically Si oxide, quantum efficiency in the DUV range is greatly reduced. The passivation layers are also easily degraded by UV illumination. Finally, for highly sensitive UV photodetection, the detectors need to be cooled to reduce dark current; the cooled detectors, however, behave like cold traps for contaminants which degrade the detectivity.In the past two decades, the emergence of UV photodetectors based on wide-bandgap (WBG) semiconductors has opened up an avenue to circumvent the above-mentioned dilemma. The WBG semiconductors such as SiC, GaN, and some group II-V compounds, typically have bandgaps exceeding ≈3.10 eV, enabling room-temperature detectors to possess fast response speed, and offering intrinsic visible-blindness (response cutoff wavelength: ≈400 nm). [14][15][16] Moreover, these semiconductors generally possess significantly higher thermal conductivity than Si, which renders them suitable for operation in harsh environments (e.g., high temperature and high power). The electron velocity of these materials at large electric fields is generally higher than that of common semiconductors, although WBG semiconductors exhibit relatively lower electron and hole mobilities. Compared with the abovementioned conventional WBG semiconductors, ultrawide-bandgap (UWBG) semiconductors, as the next generation of semiconductor materials with bandgaps significantly wider than the 3.4 eV of GaN, are particularly suitable for solar-blind DUV light detection. [17][18][19][20]

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Section: Introductionmentioning

confidence: 99%

Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

Xie

Tong

et al. 2019

Adv Funct Materials

356

243

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“…PH1000 is a commercial PEDOT:PSS-based conducting polymer with high conductivity (850 S cm −1 ) and excellent transmittance in the visible and entire UV range, including UVB and UVC. [25,26] Figure S4, Supporting Information, presents the UV-vis absorption spectra of different combinations of substrate-transparent electrodes. It can be seen that only the quartz substrate allows penetration of the entire wavelength range of light without any loss.…”

Section: Resultsmentioning

confidence: 99%

Self‐Powered Low‐Cost UVC Sensor Based on Organic‐Inorganic Heterojunction for Partial Discharge Detection

Park

Hur

2021

Small

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Power outages caused by the aging of high‐voltage power facilities can cause significant economic and social damage. To prevent such problems, it is necessary to implement a widespread and sustainable monitoring system. Partial discharge (PD) is a preliminary symptom of power equipment aging accompanying the light, typically in the UV range. UVC (200–280 nm) is more useful than UVA and UVB because of low interference from the environment owing to its solar‐blindness by the stratosphere. Therefore, to realize a wide‐range and durable diagnosis system, it is necessary to develop sensors that can selectively detect UVC, while enabling mass production at low‐cost and low power consumption. Here, a solution‐processable photodiode sensor that is inexpensive, mass‐producible, and self‐powered with selective UVC detection is developed. The optoelectronic characteristics of photodiode consisting of organic p‐polymer and inorganic n‐ZnO nanoparticles are systematically studied to determine the optimum p‐type polymer and its thickness. The device shows high‐performance: fast response time (rise/fall time: 36.6/37.0 ms) and high spectral response in the UVC region (maximum responsivity of 20 mA W−1) under self‐powered operation. Furthermore, the practical application of the device to detect PD signals with a visual alarm system under UVC release conditions is demonstrated.

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“…Stability is of importance for the practical applications of UV OPDs. However, this issue has not commonly studied to date in the most of the reported UV OPDs . One report stated that UV OPDs with m‐MTDATA donor could keep 67% of the maximum photocurrent after continuous UV illumination up to roughly 1000 minutes .…”

Section: Resultsmentioning

confidence: 99%

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

Zhu

Choy

Sha

et al. 2014

Advanced Optical Materials

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nanoparticles have been adopted to fabricate light-detection devices, which demonstrate ultrahigh photocurrent gain, nonetheless, these devices are accompanied by high operation voltage, low on/off ratio, and slow response time. [ 9 ] Different from conventional inorganic UV PDs, UV PDs utilizing organic semiconductors with fl exible bandgap engineering, less restricted substrates, and simple fabrication offer a promising pathway for low-cost, large-area, and fl exible UV PDs. [ 10 ] The majority of previously reported UV organic PDs (OPDs) achieved high effi ciency comparable with inorganic counterparts. Although some OPDs had external quantum effi ciency (EQE) over unity, a large dark current density was obtained simultaneously. Hence, low on/off ratio near or less than 10 3 was observed when these OPDs were operated at a monochromatic light with the wavelength of 365 nm and intensity of about 1 mW.cm −2 . [ 4,[11][12][13] For example, hybrid planar-bulk-heterojunction UV OPDs consisted of 4,4′,4′′-tri-(2-methylphenyl phenylamino) triphenylaine (m-MTDATA)/m-MTDATA:aluminum (III) bis(2-methyl-8-quinolinato)4-phenylphenolate (BAlq)/BAlq were demonstrated with a high EQE of 175% at a reverse voltage of 7 V, whereas the on/off ratio was approximately 1.9 × 10 3 when the intensity of 365 nm incident light was about 1.2 mW.cm −2 . [ 11 ] Bilayer UV OPDs of poly(9,9-dihexylfl uorene-2,2-diyl) (PFH)/a silane-containing triazine derivative (NSN) with a high responsivity of 0.696 A/W (corresponding EQE is 236.5%) at a large voltage of -12 V were reported that the on/off ratio was about 5 × 10 2 when the devices were illuminated by a monochromatic light of 365 nm with an intensity of 1 mW.cm −2 . [ 13 ] These high-effi ciency UV OPDs are operated at a large reverse voltage, which can effectively increase electric fi eld within OPDs, reduce the probability of excitons recombination and raise the effi ciency of excitons dissociation, thereby boosting EQE. [ 14,15 ] Nevertheless, large dark current due to the large reverse bias will also be obtained. Electron/hole blocking layers have been proposed to suppress dark current in OPDs and nanocrystal infrared PDs, dark current still remained 10 −6 to 10 −7 A/cm 2 when these devices were operated at a large reverse bias. [ 16 ] Up to now, photovoltaic mode (i.e., self-powered or zerobias operation mode) PDs were mainly reported in inorganic PDs, [ 15,17 ] but not systematically investigated in UV OPDs. Ultraviolet (UV) organic photodetectors (OPDs) operated in the photovoltaic mode, achieving a very high on/off ratio of 10 5 and a fast response time of 20 ns (a decay time of 888 ns), are demonstrated in this work. Light-induced tuning of the barrier height at the two interfaces of the carrier-extraction layer and light-induced tuning of series resistance are proposed to obtain the high on/off ratio. Fast response of the device is demonstrated through the ultrafast trap fi lling process. The high on/off ratio and fast response are simultaneously realized by introducing TiO 2 n...

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Structural spectral response tuning in organic deep ultraviolet photodetectors

Cited by 17 publications

References 31 publications

Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

Recent Progress in Solar‐Blind Deep‐Ultraviolet Photodetectors Based on Inorganic Ultrawide Bandgap Semiconductors

Self‐Powered Low‐Cost UVC Sensor Based on Organic‐Inorganic Heterojunction for Partial Discharge Detection

Photovoltaic Mode Ultraviolet Organic Photodetectors with High On/Off Ratio and Fast Response

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