Semiconductor ultraviolet detectors

Razeghi, Manijeh; Rogalski, Antoni

doi:10.1117/12.237695

Cited by 132 publications

(147 citation statements)

References 2 publications

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“…Here τ r is the recombination time, τ t is the transit time in the graphene channel. [ 36 ] Even for the high quality graphene with the mobility of 1.0 × 10 4 cm 2 V −1 s −1 , the gain is still in the scale of 10 −3 under the same conditions (100 µm channel length and 5 V bias voltage), because the ultrafast photo-induced carrier recombination time is in picosecond range. On the contrary, the photoinduced carriers are separated by the built-in fi eld in our device, resulting in a much longer recombination time.…”

Section: Communicationmentioning

confidence: 98%

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

Chen

Cheng

Wang

et al. 2015

Advanced Optical Materials

152

102

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COMMUNICATIONIn this paper, we present a highly broadband (from visible to infrared) photodetector based on chemical vapor deposition (CVD) graphene-silicon heterostructure, together to be operated in photoconductor mode. This device shows very high responsivity (>10 4 A W −1 ) at wavelength of 632 nm, where light absorption relies on silicon. More importantly, even in the infrared region (1550 nm), where light absorption only depends on the graphene, the responsivity of our detector can be as high as 0.23 A W −1 , which is much higher those by pure monolayer graphene-based devices without optically assisted structure in this spectral region. [ 13,15,24 ] The signifi cant response is mainly due to the fact that the built-in fi eld in heterostructure can effectively prolong the ultrashort lifetime of photon-induced carriers. Besides, we also fi nd three dynamic processes in the transient response: photo-induced carriers sweeping into graphene by the built-in fi eld, electrons in the depletion region diffusion back to graphene, and photo-induced carriers in the bulk silicon diffusion to graphene. Due to the fi rst mechanism, the response time of our detector is less than 3 µs, which has not been reported among graphene photoconductor/ phototransistors. [ 1 ] The structure of graphene-silicon heterostructural photodetector is schematically shown in Figure 1 a. The start wafer we employed is a lightly doped p-type silicon wafer (>100 Ω). A thin layer of SiO 2 is grown on silicon and patterned a window on top. Then, the CVD graphene (the Raman spectra is shown in Figure S1, Supporting Information) is transferred, and both electrodes are deposited on graphene. The SiO 2 layer can avoid the overlap between the electrode and silicon. A Schottky junction is thus formed at the interface between graphene and silicon. The Fermi level differences are measured by Kelvin probe force microscopy (KPFM) in the dark. As shown in Figure 1 b, the surface potential differences (approximately similar to the work function misalignment for clean samples) between graphene and silicon, and between graphene and gold are about 0.08 and 0.16 eV, respectively. Under ambient conditions, the work function of gold is around 4.8 to 4.9 eV. [ 25,26 ] By taking the intrinsic work function of graphene (≈4.56 eV) [30][31][32] into consideration, an energy band diagram is depicted in Figure 1 c. The Fermi energy of graphene should be around 0.16 to 0.26 eV. A built-in fi eld forms at the surface, which directs from silicon to graphene. The graphene not only functions as the charge transport channel, but also works as the light absorber for the light with photon energy lower than the Fermi energy.In the visible light experiment, the photodetector is characterized by the laser at wavelength of 625 nm. Optical attenuators are introduced to change the input power. DOI: 10.1002/adom.201500127Graphene is thought to be an ideal material for novel photodetectors due to its unique properties. [1][2][3] For example, its zero bandgap affords the benefi t of ultr...

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Section: Communicationmentioning

confidence: 98%

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

Chen

Cheng

Wang

et al. 2015

Advanced Optical Materials

152

102

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“…By a simple calculation considering the power density of incident light and the active area of the detector, we can obtain a photovoltaic responsivity of 9.8×10 3 V/W and a photocurrent responsivity of 9.8 mA/W. The corresponding quantum efficiency η can be deduced to be 4.8%, according to the formula η=R i hν/q, where R i is the photocurrent responsivity, h the Plank constant, ν the frequency of incident light, and q the charge of one electron [16]. We did not observe any photovoltaic signal when the ZrO 2 single crystal was irradiated by a 532 or a 632 nm laser.…”

Section: Resultsmentioning

confidence: 99%

High sensitive and ultrafast UV photodetector based on ZrO2 single crystals

Xing

Guo

Lü

2011

Sci. China Phys. Mech. Astron.

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The fast-response ultraviolet (UV) photoelectric effect in ZrO 2 single crystals with interdigitated electrodes has been investigated experimentally at room temperature. The photovoltage of ZrO 2 single crystals exhibits a linear dependence on applied bias and light power density. The photocurrent responsivity to the UV light with a wavelength of 253.65 nm is 9.8 mA/W. For the photovoltaic pulse, a rise time of 501 ps and a full width at half maximum of 1.5 ns have been obtained, when the ZrO 2 single crystal is illuminated by a 266 nm pulsed laser. These results indicate that the ZrO 2 single crystal is a promising candidate for UV photodetectors. photoelectric effect, ultraviolet photodetector, ZrO 2 single crystals PACS: 72.40.+w, 78.20.-e, 73.40.Sx

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“…There has currently been great interest in ultraviolet (UV) photodetectors due to their versatile applications, such as missile warning and tracking, engine/flame monitoring, chemical/biological agent detecting, and covert space-to-space communication, etc. [6][7][8]. In our group, we made a research on photodetector with nanopattern on the surface [9].…”

Section: Introductionmentioning

confidence: 99%

GaN surface nanostructure photodetector based on back side incidence

Zhang

Naoi

Sakai

et al. 2010

Phys. Status Solidi (c)

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The conventional photodetector can detect the intensity of the incident light by the voltage or current, but it is not sensitive to the change of the incident angle or wavelength. A GaN‐based photodetector with nanostructure on the surface has been fabricated using nanoimprint lithography (NIL). The photovoltage between p‐ and n‐layers of the surface nanostructure photodetector took 6 or 12 periods when the incident illumination angles were changed on the back side. According to the characteristics, this type of photodetector can find out the change of the incidence angle or the change of the wavelength of the incident light. The short wave absorption disturbance can be avoided when the light illuminating based on the back side. Therefore, the stability of detection can be improved and the requirement of work environment is reduced. In addition, the generation principles of periodic photovoltage are different between the light illuminating based on the back side and the surface. Thus, the surface nanostructure photodetector can be used in wider fields. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Semiconductor ultraviolet detectors

Cited by 132 publications

References 2 publications

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

High sensitive and ultrafast UV photodetector based on ZrO2 single crystals

GaN surface nanostructure photodetector based on back side incidence

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