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Terahertz detectors arrays based on orderly aligned InN nanowires.

Chen X, Liu H, Li Q, Chen H, Peng R, Chu S, Cheng B - Sci Rep (2015)

Bottom Line: The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a "transfer-printing" method.Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose.The detector showed good photoresponse as well as low noise level.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong Guangzhou 510275, China.

ABSTRACT
Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a "transfer-printing" method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series.

No MeSH data available.


(a) Schematic drawing of the “transfer printing” process. (b) SEM image of InN nanowires in array groups derived from “transfer printing” process. Scale bar: 5 μm. (c) SEM image of the aligned nanowires with source and drain electrodes deposited. Scale bar: 2 μm. (d) SEM image of the nanowire device with gate 300 nm Al2O3 deposited. (e) SEM image of the nanowire FET based on 5 aligned nanowires. Scale bar: 2 μm. (f) SEM image of the whole device. Scale bar: 100 μm.
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f6: (a) Schematic drawing of the “transfer printing” process. (b) SEM image of InN nanowires in array groups derived from “transfer printing” process. Scale bar: 5 μm. (c) SEM image of the aligned nanowires with source and drain electrodes deposited. Scale bar: 2 μm. (d) SEM image of the nanowire device with gate 300 nm Al2O3 deposited. (e) SEM image of the nanowire FET based on 5 aligned nanowires. Scale bar: 2 μm. (f) SEM image of the whole device. Scale bar: 100 μm.

Mentions: Although single InN nanowire or nano-necklace can be readily used for THz detectors such like single nanowire FET detectors, randomly distributed nanostructures are less favorable for ultimate practical applications. For simplicity and wider impact purpose, InN nanowires rather than nano-necklaces were selected to perform alignment and device fabrications. They were transferred from growth Si substrates to a patterned device substrates by a mechanical “transfer printing” process (Fig. 6a). The alignment direction is determined by the mechanic shear force due to relative motion of the two substrates. SEM image of Fig. 6b indicates that 3 ~ 6 nanowires can be successfully transferred into trench arrays after the transfer-printing process. In the following FET device fabrication, one group containing 5 nanowires was selected for demonstration. Source, drain (10 nm Ti/20 nm Au) were defined and deposited by photolithography and e-beam evaporation (Fig. 6c) to two heads and tails of the nanowires. The gate area was defined by photolithography and then 300 nm thick Al2O3 gate insulator was deposited by e-beam evaporation (Fig. 6d). The gate electrode (50 nm Pt) is finished by the assistance of focused ion beam (FIB) technique (Fig. 6e). Bow-shaped antenna with radius of 100 μm was designed to partially resonant with incidence THz wave, while the left and right lobes of the antenna were connected to source and gate electrodes, respectively. The final device structure is also seen in Fig. 6f. The reason of the typical un-symmetric source-drain electrode is for rectifying enhancement to maximize the photovoltage readout.


Terahertz detectors arrays based on orderly aligned InN nanowires.

Chen X, Liu H, Li Q, Chen H, Peng R, Chu S, Cheng B - Sci Rep (2015)

(a) Schematic drawing of the “transfer printing” process. (b) SEM image of InN nanowires in array groups derived from “transfer printing” process. Scale bar: 5 μm. (c) SEM image of the aligned nanowires with source and drain electrodes deposited. Scale bar: 2 μm. (d) SEM image of the nanowire device with gate 300 nm Al2O3 deposited. (e) SEM image of the nanowire FET based on 5 aligned nanowires. Scale bar: 2 μm. (f) SEM image of the whole device. Scale bar: 100 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542509&req=5

f6: (a) Schematic drawing of the “transfer printing” process. (b) SEM image of InN nanowires in array groups derived from “transfer printing” process. Scale bar: 5 μm. (c) SEM image of the aligned nanowires with source and drain electrodes deposited. Scale bar: 2 μm. (d) SEM image of the nanowire device with gate 300 nm Al2O3 deposited. (e) SEM image of the nanowire FET based on 5 aligned nanowires. Scale bar: 2 μm. (f) SEM image of the whole device. Scale bar: 100 μm.
Mentions: Although single InN nanowire or nano-necklace can be readily used for THz detectors such like single nanowire FET detectors, randomly distributed nanostructures are less favorable for ultimate practical applications. For simplicity and wider impact purpose, InN nanowires rather than nano-necklaces were selected to perform alignment and device fabrications. They were transferred from growth Si substrates to a patterned device substrates by a mechanical “transfer printing” process (Fig. 6a). The alignment direction is determined by the mechanic shear force due to relative motion of the two substrates. SEM image of Fig. 6b indicates that 3 ~ 6 nanowires can be successfully transferred into trench arrays after the transfer-printing process. In the following FET device fabrication, one group containing 5 nanowires was selected for demonstration. Source, drain (10 nm Ti/20 nm Au) were defined and deposited by photolithography and e-beam evaporation (Fig. 6c) to two heads and tails of the nanowires. The gate area was defined by photolithography and then 300 nm thick Al2O3 gate insulator was deposited by e-beam evaporation (Fig. 6d). The gate electrode (50 nm Pt) is finished by the assistance of focused ion beam (FIB) technique (Fig. 6e). Bow-shaped antenna with radius of 100 μm was designed to partially resonant with incidence THz wave, while the left and right lobes of the antenna were connected to source and gate electrodes, respectively. The final device structure is also seen in Fig. 6f. The reason of the typical un-symmetric source-drain electrode is for rectifying enhancement to maximize the photovoltage readout.

Bottom Line: The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a "transfer-printing" method.Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose.The detector showed good photoresponse as well as low noise level.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-Sen University, Guangdong Guangzhou 510275, China.

ABSTRACT
Nanostructured terahertz detectors employing a single semiconducting nanowire or graphene sheet have recently generated considerable interest as an alternative to existing THz technologies, for their merit on the ease of fabrication and above-room-temperature operation. However, the lack of alignment in nanostructure device hindered their potential toward practical applications. The present work reports ordered terahertz detectors arrays based on neatly aligned InN nanowires. The InN nanostructures (nanowires and nano-necklaces) were achieved by chemical vapor deposition growth, and then InN nanowires were successfully transferred and aligned into micrometer-sized groups by a "transfer-printing" method. Field effect transistors on aligned nanowires were fabricated and tested for terahertz detection purpose. The detector showed good photoresponse as well as low noise level. Besides, dense arrays of such detectors were also fabricated, which rendered a peak responsivity of 1.1 V/W from 7 detectors connected in series.

No MeSH data available.