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Complete photo-generated minority carrier's quantum tunneling device under AM1.5 illumination is fabricated by depositing tin-doped indium oxide (ITO) on n-type silicon to form a structure of ITO/SiOx/n-Si heterojunction. The work function difference between ITO and n-Si materials essentially acts as the origin of built-in-field. Basing on the measured value of internal potential (Vbi = 0.61V) and high conversion efficiency (9.27%), we infer that this larger photo-generated holes tunneling occurs when a strong inversion layer at the c-Si surface appears. Also, the mixed electronic states in the ultra-thin intermediate region between ITO and n-Si play a defect-assisted tunneling. [ABSTRACT FROM AUTHOR]

Two sorts of Gd-Co-Al ternary alloys of multi-phase structure with table-like magnetocaloric effect (MCE) suitable for the ideal Ericsson cycle have been developed. One is prepared by arc-melting Gd53Co19Al28 with the resulting alloy composed of Gd2Al, Gd2Co2Al, and GdCo0.74Al1.26 crystalline phases and the other is synthesized by suck-casting Gd52.5Co16Al31 which has a glassy structure and crystalline phases of Gd2Al and Gd2Co2Al. Metamagnetic transition of antiferromagnetic Gd2Al phase near 50K and ferromagnetic transitions of Gd2Co2Al, GdCo0.74Al1.26, and the glassy phase near 80K result in the occurring of table-like magnetocaloric effect with magnitude of ∼7 J/kg K over the temperature range from 47.5K to 77.5K for a magnetic field variation of 0 to 50 kOe. The fitting reproduces the temperature dependence of magnetic entropy change of samples and the results suggest that the magnetocaloric response of Gd2Al phase in the ternary alloys have been improved, which is crucial for the composite alloys to obtain table-like magnetocaloric effect. [ABSTRACT FROM AUTHOR]

BiFeO3 was studied as an alternative environmentally clean ferro/piezoelectric material. 200-nm-thick BiFeO3 films were grown on Si substrates with SrTiO3 as a template layer and SrRuO3 as bottom electrode. X-ray and transmission electron microscopy studies confirmed the epitaxial growth of the films. The spontaneous polarization of the films was ∼45 μC/cm2. Retention measurement up to several days showed no decay of polarization. A piezoelectric coefficient (d33) of ∼60 pm/V was observed, which is promising for applications in micro-electro-mechanical systems and actuators. [ABSTRACT FROM AUTHOR]

The (SiO[sub 2]:Er/Si/SiO[sub 2]:Er) nanometer sandwich structure, in which the thickness of the Si layer between the two SiO[sub 2]:Er barriers was varied from 1.0 to 4.0 nm with an interval of 0.2 nm, was deposited on both n[sup +]-Si and p-Si substrates using the magnetron sputtering technique. Electroluminescence (EL) from the Au/(SiO[sub 2]:Er/Si/SiO[sub 2]:Er) nanometer sandwich /n[sup +]-Si diodes under reverse biases has been observed. The EL spectrum of each diode can be fitted by three Gaussian bands with peak energies of 0.757 eV (1.64 μm), 0.806 eV (1.54 μm), and 0.860 eV (1.44 μm), and full widths at half maximum of 0.052 eV, 0.045 eV, and 0.055 eV, respectively. The marked effect of the nanometer Si layer with suitable thickness on enhancing the EL from the Er[sup 3+] in the SiO[sub 2] layers has been demonstrated. Among the diodes with Si layers having various thicknesses, the intensities of the 1.64-, 1.54-, and 1.44-μm bands of the diode with a 1.6-nm Si layer attain maxima which are 22, 8, and 7 times larger than those of the control diode without any Si layer, respectively. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Investigates the process of germanium-rich silicon germanide alloys heteroepitaxial growth on silicon. Utilization of a low-temperature solid-phase heteroepitaxial growth technique in the study; Presence of stacking faults and microtwins on films grown on silicon; Growth of germanium epitaxially to the substrate.

Demonstrates a method for annealing thin film using an electrical thermal annealing pulse technique. Application of high-current direct current electrical pulse to a conductive substrate heater material; Demonstration of aluminum thin films heating; Observation of a phase transformation in the titanate-silicon system.

Spin-lattice coupling plays an important role in both formation and understanding of the magnetism in two-dimensional magnetic semiconductors (2DMS). In this paper, the steady pressure effects on the lattice structure, Raman resonances, and magnetization of a 2DMS Cr2Ge2Te6 have been studied by both experiments and first principles calculations. It is found that the bond length of Cr-Cr decreases, the angle of Cr-Te-Cr diverges from 90°, and the Raman modes E g 3 and A g 1 show an increase with the application of external pressure. Consequently, the magnetic phase transition temperature TC decreases from 66.6 K to 60.6 K (∼9%) as the pressure increases from 0 to 1 GPa. These pressure effects not only confirm the existence of strong spin-lattice coupling but also reveal the detailed information about the lattice deformation effect on the magnetic properties in such 2DMS, which would be a benefit for the further understanding and manipulation of the magnetism in 2D materials. [ABSTRACT FROM AUTHOR]

Nanometer SiO[sub 2]/nanometer Si/nanometer SiO[sub 2] double-barrier (DB) structures, with Si layers having eleven different thicknesses from 2 to 4 nm, were deposited on n[sup +]-Si substrates using the magnetron sputtering technique. Strong electroluminescence (EL) from semitransparent Au film/DB/n[sup +]-Si structure was observed under reverse bias in a range of about 5-7 V. It is found that every EL spectrum of the structure can be decomposed into two Gaussian bands with peaks at around 1.85 and 2.25 eV, and their intensities and current swing synchronously with increasing nanometer Si layer thickness; the periodic length of swing is consistent with half of the de Broglie wavelength of the carriers. A comparison was carried out between EL from the Au/DB/n[sup +]-Si structure under reverse bias and that from the Au/DB/p-Si structure under forward bias reported previously. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Spin-lattice coupling plays an important role in both formation and understanding of the magnetism in two-dimensional magnetic semiconductors (2DMS). In this paper, the steady pressure effects on the lattice structure, Raman resonances, and magnetization of a 2DMS Cr2Ge2Te6 have been studied by both experiments and first principles calculations. It is found that the bond length of Cr-Cr decreases, the angle of Cr-Te-Cr diverges from 90°, and the Raman modes E g 3 and A g 1 show an increase with the application of external pressure. Consequently, the magnetic phase transition temperature TC decreases from 66.6 K to 60.6 K (∼9%) as the pressure increases from 0 to 1 GPa. These pressure effects not only confirm the existence of strong spin-lattice coupling but also reveal the detailed information about the lattice deformation effect on the magnetic properties in such 2DMS, which would be a benefit for the further understanding and manipulation of the magnetism in 2D materials. [ABSTRACT FROM AUTHOR]

Field-effect transistors (FETs) combined with a microfluidic system allow for the electrical detection of charged materials moving in a microfluidic channel. Here, we demonstrate trench-shaped silicon FETs with the combination of a microfluidic channel that can be used for simultaneous electrical and optical detection of charged fluorescent beads. The n-channel silicon trench FETs have a maximum transconductance of 1.83 × 10 -5  S at near-zero gate bias voltage, which is beneficial for the high sensitivity of electrical detection. The optical transparency and physical robustness of the integrated microfluidic channel are achieved by a polydimethylsiloxane (PDMS)/glass hybrid cover combining the good sealing characteristics of PDMS, and the thin and flat properties of glass. Device evaluation methodologies and measurement approaches are also presented demonstrating a synchronized time-lapse imaging and electronic detection of bead transport. The proposed device and design consideration could advance the promise of electronic sensing to measure potential differences induced by charged analytes., (© 2022 Author(s).)

Flexible graphene transistors built on a biocompatible Parylene C substrate would enable active circuitry to be integrated into flexible implantable biomedical devices. An annealing method to improve the performance of a flexible transistor without damaging the flexible substrate is also desirable. Here, we present a fabrication method of a flexible graphene transistor with a bottom-gate coplanar structure on a Parylene C substrate. Also, a current annealing method and its effect on the device performance have been studied. The localized heat generated by the current annealing method improves the drain current, which is attributed to the decreased contact resistance between graphene and S/D electrodes. A maximum current annealing power in the Parylene C-based graphene transistor has been extracted to provide a guideline for an appropriate current annealing. The fabricated flexible graphene transistor shows a field-effect mobility, maximum transconductance, and a I on /I off ratio of 533.5 cm 2 /V s, 58.1  μ S, and 1.76, respectively. The low temperature process and the current annealing method presented here would be useful to fabricate two-dimensional materials-based flexible electronics.

An optical method with single-gene sensitivity for cell detection based on laser guidance was explored. Guided by the optical force from a weakly focused laser beam, a cell will move along the laser axis. Cells with different properties experience different optical forces and thus guidance speeds. The guidance speeds of the TC-1 cell and its genetically modified counterpart with only one gene change, L-10 cell, were studied under the same conditions. The results demonstrated that this laser guidance-based speed-measurement method can precisely distinguish cells that differ by only one gene.