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- Li, Junjie, 1995, et al.
(författare)
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Investigation of Noise Properties in the InP HEMT for LNAs in Qubit Amplification: Effects From Channel Indium Content
- 2024
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Ingår i: IEEE Journal of the Electron Devices Society. - 2168-6734. ; 12, s. 243-248
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Tidskriftsartikel (refereegranskat)abstract
- The InP high-electron-mobility transistor (HEMT) is employed in cryogenic low-noise amplifiers (LNAs) for the readout of faint microwave signals in quantum computing. The performance of such LNAs is ultimately limited by the properties of the active InxGa1-xAs channel in the InP HEMT. In this study, we have investigated the noise performance of 100-nm gate-length InP HEMTs used in cryogenic LNAs for amplification of qubits. The channel indium content in the InP HEMTs was 53, 60 and 70%. Hall measurements of the epitaxial materials and dc characterization of the InP HEMTs confirmed the superior transport properties of the channel structures. An indirect method involving an LNA and small-signal noise modeling was used for extracting the channel noise with high accuracy. Under noise-optimized bias, we observed that the 60% indium channel InP HEMT exhibited the lowest drain noise temperature. The difference in LNA noise temperature among InP HEMTs became more pronounced with decreasing drain voltage and current. An average noise temperature and average gain of 3.3 K and 21 dB, respectively, for a 4-8 GHz three-stage hybrid cryogenic LNA using 60% indium channel InP HEMTs was measured at a dc power consumption of 108 μW. To the best of the authors’ knowledge, this is a new state-of-the-art for a C-band LNA operating below 1 mW. The higher drain noise temperature observed for 53 and 70% indium channels InP HEMTs can be attributed to a combination of thermal noise in the channel and real-space transfer of electrons from the channel to the barrier. This report gives experimental evidence of an optimum channel indium content in the InP HEMT used in LNAs for qubit amplification.
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| 2. |
- Li, Kefei, et al.
(författare)
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RILEM recommendation from TC 289-DCM: guideline for designing and operating long-term marine exposure sites
- 2024
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Ingår i: Materials and Structures/Materiaux et Constructions. - 1359-5997. ; 57:3
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Tidskriftsartikel (refereegranskat)abstract
- This guideline prescribes the technical requirements for the design and operation of long-term exposure sites in marine environments. The technical content includes the design of exposure site, the monitoring of environmental conditions, the monitoring of exposed specimens, the data management and the maintenance of exposure facilities. The design of exposure site covers the choice of exposure sites, the exposure infrastructure and facilities, exposure specimens and their placing and protection. Then, the guideline defines the environmental factors to be monitored and the corresponding monitoring methods. For the exposed specimens, the guideline specifies the target performance to monitor, the sampling, the testing and the reporting of exposure results. The data management deals with such aspects as the data storage, data transmission and the data sharing. At the end, the guideline gives the principles for the maintenance of the exposure facilities. This guideline summarizes the best practice of long-term exposure in marine environments, and it is expected to support the normalization of exposure practice and to generate more added values from this practice.
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