Hf-Contacted High-Performance Air-Stable n-Type Carbon Nanotube Transistors

Liu, Xiaohui; Wu, Zhongqi; Hong, Delin; Wang, Weifeng; Xue, Chenqiao; Cai, Xiang; Ding, Shuting; Yao, Fenfa; Jin, Chuanhong; Wang, Sheng

doi:10.1021/acsaelm.1c00767

Cited by 10 publications

(7 citation statements)

References 33 publications

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“…The substrate is highly resistive silicon with a SiO 2 film of 300 nm to reduce parasitic capacitance. Titanium (Ti)/palladium (Pd) (0.3/80 nm) film and hafnium (Hf) (80 nm) film are used as the contact electrodes , to form an asymmetric interdigitated structure to enhance output current. The active area is 100 μm 2 with a channel length of 200 nm and a total width of 500 μm.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast Carbon Nanotube Photodetectors with Bandwidth over 60 GHz

et al. 2023

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The future interconnect links in intra-and interchip require a photodetector with high bandwidth, ultrawide waveband, compact footprint, low cost, and compatible integration process with silicon complementary metal−oxide− semiconductor (CMOS) technology. Here, we demonstrate a CMOS-compatible carbon nanotube (CNT) photodetector that exhibits high responsivity, high bandwidth, and broad spectral operation over all optical telecommunication bands based on highpurity CNT arrays asymmetrically contacted by palladium and hafnium electrodes. The ultrafast CNT photodetector demonstrates the 100 Gbit/s Nyquist-shaped on−off keying (OOK) signal transmission, which can address the demand for high-speed optical interconnects in and between data centers. Furthermore, the photodetector exhibits a bandwidth over 60 GHz by scaling down the active area to 20 μm 2 . As the CNT photodetectors are fabricated by a doping-free process, it also provides a cost-effective solution to integrate CNT photonic devices with CNT-based CMOS-integrated circuits. Our work paves a way for future CNT-based highspeed optical interconnects and optoelectronic-integrated circuits (OEICs).

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Section: Resultsmentioning

confidence: 99%

Ultrafast Carbon Nanotube Photodetectors with Bandwidth over 60 GHz

et al. 2023

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“…In the CNT photodetector, electrons are abundant close to the Hf electrode, as the work function of Hf (3.9 eV) is nearly aligned with the conductance band of CNTs. [ 35 ] Additionally, the holes are abundant close to the Pd electrode, as the work function of Pd (5.1 eV) is aligned with the valence band of CNTs. [ 36 ] The electrons and the holes can tunnel into the channel easily under the reverse bias due to the small bandgap of CNTs (≈0.46 eV), and we use the local n‐type doping layer to raise the tunneling barrier and reduce the dark current under reverse bias.…”

Section: Resultsmentioning

confidence: 99%

Shortwave Infrared Polarization Imaging and Monolithic Integrated Polarization Amplification Systems Based on Aligned Carbon Nanotube Arrays

Cai,

Wu,

Han

et al. 2023

Adv Funct Materials

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Next‐generation shortwave infrared (SWIR) imaging systems generally require a multidimensional information sensing capability (including intensity, wavelength, polarization, phase, etc.), a highly integrated photodetector unit, and information processing, allowing for miniaturization and low‐cost production. However, traditional polarized SWIR imaging systems with integrated polarizer arrays as supplementary filters and silicon‐based amplifying circuits are complicated and very expensive. Here, a SWIR polarization‐sensitive photodetector and a monolithic integrated polarization amplification system (MIPAS) based on well‐aligned carbon nanotube (CNT) arrays are demonstrated. The polarization‐sensitive CNT photodetector exhibits anisotropic ratios of ≈5.18 and ≈7.56 at 1800 and 2000 nm wavelengths, respectively, and high‐resolution characteristics that can be utilized to image SWIR laser spots with a radius of less than 10 µm. Furthermore, MIPAS including a CNT field‐effect transistor, a CNT loading resistor, and a polarization‐sensitive CNT photodetector is used to increase the anisotropic ratio of the CNT photodetector. The amplified anisotropic ratio is improved up to 173 and 243 at 1800 and 2000 nm wavelengths, respectively, which is the maximum reported in the SWIR band. Our work demonstrates that the CNT polarization‐sensitive photodetector has the potential for SWIR polarization imaging with a monolithic integrated polarization amplification system.

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“…The detailed fabrication process of the CNT photodetector is described in the Methods and Figure S4. Due to their suitable metal work function and good wetting with CNT, Pd is used as the p-type contact electrode and Hf is used as the n-type contact electrode. , A false-color SEM image showing an as-fabricated CNT photodetector with a channel length ( L ch ) of 200 nm and a total channel width ( W ch ) of 200 μm is shown in Figure d. The finger structure is used to enhance the output photocurrent and improve the signal-to-noise ratio (SNR).…”

Section: Resultsmentioning

confidence: 99%

High-Speed Carbon Nanotube Photodetectors for 2 μm Communications

Wang

Cai

et al. 2023

ACS Nano

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In the era of big data, the growing demand for data transmission capacity requires the communication band to expand from the traditional optical communication windows (∼1.3–1.6 μm) to the 2 μm band (1.8–2.1 μm). However, the largest bandwidth (∼30 GHz) of the current high-speed photodetectors for the 2 μm window is considerably less than the developed 1.55 μm band photodetectors based on III–V materials or germanium (>100 GHz). Here, we demonstrate a high-performance carbon nanotube (CNT) photodetector that can operate in both the 2 and 1.55 μm wavelength bands based on high-density CNT arrays on a quartz substrate. The CNT photodetector exhibits a high responsivity of 0.62 A/W and a large 3 dB bandwidth of 40 GHz (setup-limited) at 2 μm. The bandwidth is larger than that of existing photodetectors working in this wavelength range. Moreover, the CNT photodetector operating at 1.55 μm exhibits a setup-limited 3 dB bandwidth over 67 GHz at zero bias. Our work indicates that CNT photodetectors with high performance and low cost have great potential for future high-speed optical communication at both the 2 and 1.55 μm bands.

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Hf-Contacted High-Performance Air-Stable n-Type Carbon Nanotube Transistors

Cited by 10 publications

References 33 publications

Ultrafast Carbon Nanotube Photodetectors with Bandwidth over 60 GHz

Ultrafast Carbon Nanotube Photodetectors with Bandwidth over 60 GHz

Shortwave Infrared Polarization Imaging and Monolithic Integrated Polarization Amplification Systems Based on Aligned Carbon Nanotube Arrays

High-Speed Carbon Nanotube Photodetectors for 2 μm Communications

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