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By in situ depositing Y2O3 on a pristine p-In0.53Ga0.47As surface under ultra-high vacuum, we have attained a low interfacial trap density (Dit) of (2–5) × 1011 eV−1cm−2 from the mid-gap to the valence band edge. The Dit values were extracted from the conductance contours measured from 300 K to 77 K. The small frequency dispersions of 1.2%/dec (300 K) and 0.28%/dec (77 K) in the accumulation region of the capacitance–voltage (CV) characteristics and very small frequency-dependent flatband voltage shifts of 0.021 V/dec (300 K) and 0.011 V/dec (77 K) indicate low border trap densities and low Dit's; these experimental results have not been achieved in previous reports of oxide/p-In0.53Ga0.47As. The Y2O3/p-In0.53Ga0.47As heterostructure also exhibited a high thermal stability of 800 °C, as observed by the low Dit values, small CV frequency dispersions, and an abrupt interface without inter-diffusion in cross-sectional scanning transmission electron microscopy images. Our work has demonstrated a long-sought remedy for the effective passivation of p-type In0.53Ga0.47As, paving the way to high-performance electronic and optoelectronic In0.53Ga0.47As devices.

Nickel micro-electroforming was integrated with 355-nm wavelength ultraviolet laser process to fabricate the through silicon via (TSV) for 4G communication device packaging. This technology was applied to package the high-frequency solidly mounted resonator (SMR). Different parameters including laser power, focus length, frequency, and termination diameter were explored to characterize the quality of TSV for laser drilling. The thickness of silicon sample of 550 μm was drilled. The diameter of the silicon by laser drilling was 100–110 μm, where the taper was about 1.6° and the aspect ratio was about 5. The relationship between micro-electroforming deposition thickness and time were obtained. The deposition thickness was carried out by various current densities under 0.5 Amps per square decimeter (ASD), 1 ASD, 2 ASD, and 4 ASD, respectively, to analyze the electroplating quality. In addition, nanoindenter, energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) were used to analyze the material characteristics of micro-electroforming samples. Laser drilling and micro-electroforming were integrated to package the high-frequency SMR. The result shows that the S 11 parameter was − 3.5 dB under the frequency of 2.5 GHz. This TSV with micro-electroforming process shows potential use for 4G packaging application.

The in-situ deposited high κ gate dielectrics, Ga 2 O 3 (Gd 2 O 3 )[GGO], Y 2 O 3 , HfO 2 , and Al 2 O 3 , on freshly molecular beam epitaxy (MBE) grown In 0.53 Ga 0.47 As (InGaAs) have perfected the interfacial electronic (chemical) characteristics, thus achieving low interfacial trap densities (D it ) and high-temperature thermal stability. These enable fabrication of self-aligned inversion- channel InGaAs metal-oxide-semiconductor field-effect- transistors (MOSFETs) using a CMOS compatible process, giving very high drain currents (I d ) of 1.05-1.8 mA/μm and transconductances (G m ) of 0.714-0.98 mS/μm in 1μm gate length (L g ) devices; Synchrotron radiation photoemission spectroscopy (SRPES) reveals no AsO x residue at the in-situ atomic layer deposited (ALD)-Al 2 O 3 /InGaAs interface, while some AsO x remains using the ex-situ method. The in-situ 1μm L g GGO/Ge pMOSFETs have given I d of 0.496 mA/μm, G m of 0.178 mS/ μm, and effective hole mobility of 389 cm2/V s. On the formation of Schottky barrier height (SBH) of Ag/GaAs, SRPES core-level data show that Ag adatoms effectively passivate the surface As-As dimers in the initial Ag deposition. A SBH of 0.38 eV is secured at Ag 0.25 A thick prior to the formation of an Ag metal. The final SBH is similar to the measured value at the initial Ag deposition.

This study utilizes 355 nm ultraviolet (UV) laser' micro electroforming process with supercritical fluid to package 4G solidly mounted resonator (SMR) wafer. The diameter of drilling hole was 100–150 μm with the wafer thickness of 550 μm' and the component was packaged by the embedded circuit and through silicon via (TSV) technology. Experiment results show the aspect ratio was around 5 and the sidewall slope was about 2 degrees. Micro-Ni electroforming was used to form the conductive channel' reduced the process time within four hours. This process and analysis technology obtained the minimum package area' increased the intensity' gained the electrical and thermal properties' and was able to pre-judge the impact of the package components before packaging.

This paper introduces a method combining a general electrothermal network π-model in system level and the associated mathematical technique, Green's theorem, in terms of the adopted materials and system geometries to build up an equivalent electrothermal circuit model (EETCM) for efficient thermal analysis and behavior prediction in a thermal system. Heat conduction and convection equations in integral forms are derived using the theorem and successfully applied for the thermal analysis of a 3-D optical stack, vertical-cavity surface-emitting lasers (VCSELs) on a silicon optical bench. The complex stack structure in conventional simulators can be greatly simplified using the method by well-predicting probable heat flow paths, and the simplification can eventually achieve the goal of CPU time saving without having complicated mesh designing or scaling. By comparing the data from the measurement, the finite-element simulation, and the method calculation shows that an excellent temperature match within ±~0.5 °C and 90% CPU time saving can be realized.

Using room-temperature surface photovoltage spectroscopy (SPS) we have characterized four GaAlAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (pHEMT) structures with varied quantum well compositional profiles fabricated by molecular beam epitaxy. Signals have been observed from every region of the samples. The normalized first derivative of the surface photovoltage (SPV) signal with respect to photon energy from the InGaAs quantum well channel can be accounted for by a line shape function which is the first derivative of a step-like two-dimensional density of states and a Fermi level filling factor. A detailed line shape fit makes it possible to evaluate the Fermi energy, and hence the concentration of two-dimensional electron gas in addition to the energies of the intersubband transitions. The differences of intersubband transition energies are attributed to the surface segregation effects of indium atoms. In addition, other important parameters of the system such as the Al composition and the properties of the GaAs/GaAlAs superlattice (SL) buffer layer also are obtained from the SPV spectra. The results demonstrate the considerable potential of SPS for the contactless and nondestructive characterization of pHEMT structures at room temperature.

This paper presents a numerical and experimental study concerning cooling characteristics of a pulsating heated vertical plate sandwiched between a substrate of phase change material (PCM) and an enclosure of water, forming a composite vertical rectangular enclosure. The vertical plate is assumed to have a uniform pulsating (on/off) volumetric heat source. The PCM considered in the present study is n-Octadecane. In the finite-difference simulation, the two-dimensional buoyancy-driven fluid flows developed in both the water-filled subenclosure and the molten PCM region of the PCM-filled subenclosure were modeled as laminar Newtonian fluid flow adhering to the Boussinesq approximation. Meanwhile, two-dimensional conduction is accounted for the plate heater as well as the solid PCM zone. Numerical results are presented to unveil the cooling behavior of the pulsating heat-generating plate through the PCM substrate and water-filled enclosure. Results of the parametric simulations reveal that the water layer has the better capability of heat dissipation than the PCM substrate. Heat dissipation from the plate through the PCM substrate is mainly via the latent heat absorption as associated with melting phenomenon. Moreover, numerical results obtained are compared with the corresponding experiments.

A glass polycapillary lens that both bends and focuses a cold neutron beam has been designed and constructed. The bender focuser guides part of the incident beam away from its line of sight and focuses it to a spot of width 0.65 mm at a distance 95 mm from the lens exit and 20 mm below the bottom edge of the beam path, with a gain of 20 in neutron current density. The neutron transmission characteristics of the lens have been determined with two types of position-sensitive detectors, a charge injection device, and an imaging plate. The lens has been tested with prompt gamma measurements on a gadolinium shard and titanium foil.

Using room-temperature surface photovoltage spectroscopy (SPS), we have characterized a GaAlAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (pHEMT) structure. Signals have been observed from every region of the sample. From a line shape fit to the normalized first derivative of the surface photovoltage signal with respect to photon energy, the two-dimensional electron gas density (Ns) was obtained and found to be in good agreement with Hall measurement. The Al composition and the properties of the GaAs/GaAlAs superlattice buffer layer also were obtained from the SPS spectrum. The results demonstrate the considerable potential of SPS for the contactless and nondestructive characterization of pHEMT structures at room temperature.

Taiwan Photon Source (TPS) is under construction at the National Synchrotron Radiation Research Center (NSRRC). This 518 m circumference synchrotron accelerator will generate 3 GeV and 500 mA high-energy X-rays. Absorbers in the storage ring will receive relatively high power densities (at a distance of 2.2 m from the dipole source). Three types of crotch absorbers for B1–B3 storage chambers were designed and prototyped. An end absorber in B3 is also designed and implemented to protect the downstream components in the chamber from being heated by the synchrotron radiation. Intensive vacuum brazing between Oxygen Free High Conductivity copper (OFHC) and stainless steel was carried out while fabricating the absorber assembly. The analysis, design and construction of several absorbers are reported in this paper.

In this paper we present the results of surface temperature control of silicon nanowires by using fluorescent thermometry at the nanometer scale. Rhodamine B is one of the stable fluorescent molecules, which rely on the characteristic of temperature-dependent change in fluorescent intensity, and it was used for nano-scale surface temperature sensing interface. The resistive heating on Si nanowires was carried out with applying voltage potential of 6 ~ 12 V. Surface-temperature measurement was performed by converting the changes in fluorescent intensity with calibration curve of Rhodamine B. The temperature at the central line along nanowires increasing from 30 degrees to 35~70 degrees was observed.

In our previous work, we first propose the Au/AuBe is a good ohmic contact material to p-type ZnTe. After apply the material to II-VI light emitting diode, the operation voltage as low as 2.4V can be observed. The II-VI blue light emitting diode (LED) were grown in a RIBER 32P system with Zn(6N), Se(6N), Te(6N), Cd(6N) on (001) GaAs+ substrate. The structure consisted of a GaAs:Si(n+) buffer layer, ZnSe:C1 (0.5um), ZnSe(200A)/ZnCdSe (100A) multiple quantum well, ZnSe(200A), ZnSe:N(0.3um), ZnSe:N/ZnTe:N multilayer and ZnTe:N (300A). Standard photolithography technology was doen to fabricate the diode. The mesa etch was done by (formula available in paper) etching solution. The p-type ohmic was done by AuBe/Au metal. The emission wavelength was 530nm (room temperature) and 495 (30K) with 2.4V under CW operation. Since low operation voltage introduced less heat in the device, better thermal behavior can be expected with this low operation voltage.

A laser opening technique is employed as the photolithography process to form selective emitter (SE) structures on multi-crystalline silicon (mc-Si) substrates for the large-area (156 × 156 × mm 2 ) solar-cell industry. The best efficiency of 16.35% is obtained with the developed SE structure after a damage removal process with optimisation of heavily and lightly doped dopants, which yields a gain of 0.88% absolute compared with that of a reference cell. Significantly, the SE mc-Si solar cell without the damage removal process can also reach a gain of 0.48% absolute. The developed SE process has simplicity, reliability, is fast, cost-effective, and could be effectively applied to mass production in industrial applications.

Magnetic properties and microstructure of directly quenched Nd9.5Fe72.5Ti3−xMxB15 (M=Nb and Zr; x=0–3) bulk magnets in rod form with a diameter of 0.9 mm have been studied. Proper Nb or Zr substitution for Ti has been found to well modify phase constitution and to refine the grain size from 200 to 50–100 nm effectively. Accordingly, the magnetic properties of the rods are enhanced remarkably from Hic=6.2 kOe and (BH)max=5.6 MG Oe for Nd9.5Fe72.5Ti3B15 to Hic=6.7–15.4 kOe and (BH)max=6.0–8.2 MG Oe for Nd9.5Fe72.5Ti3−xMxB15. The optimum magnetic properties of Br=6.6 kG, Hic=9.6 kOe, and (BH)max=8.2 MG Oe can be achieved for Nd9.5Fe72.5Ti2.5Zr0.5B15 alloy, while the highest coercivity of Hic=15.4 kOe [Br=5.9 kG and (BH)max=7.0 MG Oe] is obtained for Nd9.5Fe72.5Nb3B15. Their high permanent magnetic property arises mainly from the existence of a large volume fraction of 2:14:1 phase, finer grain size, and the existence of grain boundary phase.

A novel, relatively simple and cost effective method is reported to fabricate suspended silicon nanowires. This method allows for the production of suspended silicon nanowires using anisotropic wet etching and thermal oxidation of single crystalline silicon. The dimensions of the silicon nanowires fabricated with the proposed method are evaluated. The vibration properties of the nanowires obtained by heterodyne laser doppler interferometer show the potential of being nanomechanical sensors.

A resonance neutron tomography project was carried out at the National Bureau of Standards which included (1) the construction of the reactor-based resonance neutron safeguards experimental system and the making of provisions for its use, and (2) the initial tomographic construction of a nuclear waste container.