Publications by authors named "Hei-Man Yau"

Article Synopsis
  • The matching layer is essential for enhancing the performance of piezoelectric ultrasound transducers because it helps bridge the significant acoustic impedance gap between the transducer materials and human tissues.
  • A new manufacturing technique allows for tuning the acoustic impedance of an alumina-epoxy composite from 6.50 to 9.47 MRayl by adjusting the compression pressure and component ratios, with optimal performance achieved at 62.4 MPa using an 80% alumina mixture.
  • This innovative matching layer shows minimal attenuation at high frequencies (-10 dB/mm at 40 MHz) and superior impedance, making it highly effective for improving ultrasound transducer performance, particularly in medical imaging.
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Integration of transition metal dichalcogenides (TMDs) on ferromagnetic materials (FM) may yield fascinating physics and promise for electronics and spintronic applications. In this work, high-temperature anomalous Hall effect (AHE) in the TMD ZrTe thin film using a heterostructure approach by depositing it on a ferrimagnetic insulator YIG (YFeO, yttrium iron garnet) is demonstrated. In this heterostructure, significant anomalous Hall effect can be observed at temperatures up to at least 400 K, which is a record high temperature for the observation of AHE in TMDs, and the large is more than 1 order of magnitude larger than those previously reported values in topological insulators or TMD-based heterostructures.

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An artificial synapse, such as a memristive electronic synapse, has caught world-wide attention due to its potential in neuromorphic computing, which may tremendously reduce computer volume and energy consumption. The introduction of layered two-dimensional materials has been reported to enhance the performance of the memristive electronic synapse. However, it is still a challenge to fabricate large-area layered two-dimensional films by scalable methods, which has greatly limited the industrial application potential of two-dimensional materials.

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Thin film flexoelectricity is attracting more attention because of its enhanced effect and potential application in electronic devices. Here we find that a mechanical bending induced flexoelectricity significantly modulates the electrical transport properties of the interfacial two-dimensional electron gas (2DEG) at the LaAlO_{3}/SrTiO_{3} (LAO/STO) heterostructure. Under variant bending states, both the carrier density and mobility of the 2DEG are changed according to the flexoelectric polarization direction, showing an electric field effect modulation.

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Conducting bridge random access memory (CBRAM) is one of the most promising candidates for future nonvolatile memories. It is important to understand the scalability and retention of CBRAM cells to realize better memory performance. Here, we directly observe the switching dynamics of Cu tip/SiO/W cells with various active electrode sizes using in situ transmission electron microscopy.

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Amorphous black phosphorus (a-BP) ultrathin films are deposited by pulsed laser deposition. a-BP field-effect trans-istors, exhibiting high carrier mobility and moderate on/off current ratio, are demonstrated. Thickness dependence of the bandgap, mobility, and on/off ratio are observed.

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