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A practical method to use sunlight to generate storable chemical energy could dramatically change the landscape of global energy generation. One of the fundamental requirements of such an "artificial photosynthesis" scheme is a light capture and conversion approach capable of generating the required chemical potentials (e.g. >1.23 V for splitting water into H2 and O2). An approach based on inorganic light absorbers coupled directly to oxidation and reduction catalysts is being developed in the Joint Center for Artificial Photosynthesis (JCAP). P-type III-V semiconductors with a high surface area can be used as high current density photocathodes. The longevity under operation of these photocathodes can be improved by the use of conformal metal oxides deposited by atomic layer deposition. [ABSTRACT FROM AUTHOR]

This paper reports on a successful demonstration of the use and reliability of Cu/Sn microbumps for the fine pitch interconnection of heterogeneous semiconductor die. InP die have been bonded to Si substrates using a 6.4 mm × 5.12 mm area array of alloyed Cu/Sn microbumps on 10 μm pitch. After bonding, 256 separate channels, each connecting 1280 microbumps, were electrically tested on each die; the channel yield was used to estimate the operability of the 640 × 512 arrays, which was found to be greater than 99.99% for both InP-Si die pairs and Si-Si control die pairs. After 500 thermal cycles from −40 °C to 125 °C, no significant change in the channel yield was seen for the homogeneous Si-Si die pairs. The InP-Si die pairs underfilled with an experimental epoxy had a 2.8% decrease in channel yield while those die pairs without the underfill saw a 13.9% decrease. The channels that failed during thermal cycling were predominately located near the edges of the die pairs, indicating that the bump failures were due to the difference in thermal expansion between InP and Si. Cross-sectional SEM images taken from the edge areas of both underfilled and non-underfilled InP-Si die pairs were used to assess the failure mode in the non-underfilled samples and to demonstrate the positive effects of the use of the underfill. [ABSTRACT FROM PUBLISHER]

Auger Electron Spectroscopy (AES) and Electron Energy Loss Spectroscopy (EELS) have been performed in order to investigate the InP(100) surface subjected to ions bombardment. The InP(100) surface is always contaminated by carbon and oxygen revealed by C-KLL and O-KLL AES spectra recorded just after introduction of the sample in the UHV spectrometer chamber. The usually cleaning process of the surface is the bombardment by argon ions. However, even at low energy of ions beam (300 eV) indium clusters and phosphorus vacancies are usually formed on the surface. The aim of our study is to compare the behaviour of the surface when submitted to He+ or H+ ions bombardment. The helium ions accelerated at 500V voltage and for 45 mn allow removing contaminants but induces damaged and no stoichiometric surface. The proton ions were accelerated at low energy of 500 eV to bombard the InP surface at room temperature. The proton ions broke the In-P chemical bonds to induce the formation of In metal islands. Such a chemical reactivity between hydrogen and phosphorus led to form chemical species such as PH and PH3, which desorbed from the surface. The chemical susceptibly and the small size of H+ advantaged their diffusion into bulk. Since the experimental methods alone were not able to give us with accuracy the disturbed depth of the target by these ions. We associate to the AES and EELS spectroscopies, the TRIM (Transport and Range of Ions in Matter) simulation method in order to show the mechanism of interaction between Ar+, He+ or H+ ions and InP and determine the disturbed depth of the target by argon, helium or proton ions. [ABSTRACT FROM AUTHOR]

We investigate the electronic and optical properties of InP in the zincblende phase using a plane wave basis with local density approximation (LDA). The Kohn Sham bandstructure of InP is obtained, from which the bandgap of the material is calculated. The density of states (DOS) of the two atoms of InP are also obtained. The complex dielectric function of InP is obtained from the derivative of the wave function with respect to the wave vectors in three dimension. The peaks in the spectrum of the complex part of the complex dielectric function are explained on the basis of the DOS. Refractive index, extinction coefficient and reflectivity of InP are also computed from the complex dielectric function. [ABSTRACT FROM PUBLISHER]

A fully differential master-slave track-and-hold amplifier is designed and fabricated with a 320-GHz-fT-InP DHBT process. This circuit shows an input bandwidth of 16 GHz and a −3.5 dB forward gain. At 4 GSa/s and for a −4 dBm single-ended input signal, the circuit has a total harmonic distortion lower than −57 dB and −38.6 dB respectively at low frequency and up to 10 GHz. Time domain measurement at 4 GSa/s is also presented. [ABSTRACT FROM PUBLISHER]

A fully differential 40 Gsample/s Track and Hold Amplifier (THA) with high dynamic range and large bandwidth is designed and fabricated in a 210 GHz-ƒT -InP-DHBT process. To optimize the THA performances, the THA core characteristics are extensively investigated, both by simulations and measurements. Spectral measurements performed on the THA in track mode give a THD and a SFDR of −42.5 dB and −43.8 dB, respectively, for input frequency up to 9 GHz and input voltage up to −2 dBm. This THD is equivalent to 6.7 ENOB. Time domain measurement demonstrates the THA performances for 40 GHz sampling with 2 GHz sinusoidal input signal. [ABSTRACT FROM PUBLISHER]

A 2:16 DEMUX IC with clock phase adjustment has been successfully designed, fabricated, and tested as an interfacing component in 30 Gbps and higher transmission systems using HRL's 0.25 μm low power InP DHBT technology with ft of 400 GHz. The novel clock phase adjustment circuit described here allows multiple DEMUXs to be automatically synchronized eliminating the need of complex clock recovery circuits. The IC uses 1460 DHBTs and consumes only 1.85 W of power demonstrating the feasibility of InP DHBTs in low power and large integration ICs. [ABSTRACT FROM PUBLISHER]

Two MMIC amplifiers have been developed in coplanar technology using 50-nm InAlAs/InGaAs HEMTs. The first is a sing-stage amplifier which used balanced double-stub matching networks for both input and output impedances matching. Measured gain is 8.2 dB @ 81.3 GHz, and the 3-dB bandwidth is at least 13.7 GHz. The second is a two-stage common-source power amplifier. A “#” type distributed transmission line networks has been developed and applied to inter-stage and output stage matching networks. This technique propose a new and efficient approach for impedance matching between transistors where DC blocking and separate bias supplies to the active devices are required. Measured gain is 10.1 dB @ 84 GHz and the 3-dB bandwidth is 14.7 GHz. The saturated power is 11.6 dBm @ 85 GHz, 3.6 dB higher than the above-mentioned single-HEMT amplifier. Measured data are in agreement with the simulation results. [ABSTRACT FROM PUBLISHER]

Impulse noise has severe impact on the whole family of xDSL technologies. This paper focuses on analysis of impulse noise that is present on subscriber lines and describes three basic impulse noise models, i.e. REIN, SHINE and PEIN. [ABSTRACT FROM PUBLISHER]

We review the state-of the art of long-wavelength VCSELs. Furthermore, the short-cavity concept which has already been successfully implemented in 1.55 μm devices is extended to 1.3 μm devices resulting in excellent static and dynamic device properties. In particular, high output powers of 1.8 mW at an ambient temperature of 80 °C, high differential quantum efficiencies up to 56% and wall-plug efficiencies up to 36% at room-temperature are reported. Small-signal modulation bandwidths in excess of 15 GHz are presented. The large-signal modulation at a bit-rate of 25 Gbps is investigated. [ABSTRACT FROM PUBLISHER]

High speed photodetectors are most sophisticated optoelectronic devices, because it has high photo sensitivity, and allow a large wavelength range of detection as a receiver from 750 nm to 1.3–1.55 µm in the optical communication system. Since the last decade, the electrical and optical characteristics of photodetectors have been investigated to improve their performance and price. We have worked on two different type of infrared photodetectors based on nanowire. One photodetector was p-n photodiode, and the other one was p-i-n structure. We investigated the detector performance at 77K–300K temperature corresponding with wavelength in darkness and under illumination as regarding breakdown voltage, sensitivity, and quantum efficiency. We have also compared the differences between the two photodetectors performance characteristics. [ABSTRACT FROM PUBLISHER]

In this work, ammonium sulfide ((NH4)2S) solution was used to passivated the surfaces of InP substrate. The optical properties were measured by PL (Photoluminescence) measurement, the luminescence intensity increased about 7 times when the passivated time was 15 min. The reasons of enhanced luminescence were also discussed. After passivating, the surface morphology and electrical properties were analyzed by atomic force microscopy (AFM) and Hall effect, respectively. [ABSTRACT FROM PUBLISHER]

The intermixing characteristics of three widely used combinations of InP based quantum wells (QW) (InGaAsP/InGaAsP, InGaAs/InGaAsP, InP/InGaAs) are investigated using the impurity-free vacancy disordering (IFVD) technique. We demonstrate that the shift of the bandgap energy is highly dependent on the concentration gradient of the as-grown wells and barriers, as well as the thickness of the well, with thinner wells more susceptible to interdiffusion at the interface between the barrier and well. According to our results, the InGaAsP/InGaAsP and InGaAs/InP are well suited for applications requiring a wide range of bandgap values within the same wafer. The InGaAs/InP resulted in a blue shift of more than 200 nm, while the InGaAsP/InGaAsP provided approximately 100 nm. For the InGaAs/InGaAsP system, we suggest that although a decent bandgap shift of near 80 nm can be obtained, its use is limited due to the significant broadening of the photoluminescence spectrum that was observed. The effect of the top InGaAs layer over the InP cladding is also investigated, and leads to a simple way to obtain three different bandgaps in a single intermixing step. [ABSTRACT FROM AUTHOR]

Experimental results are reported on field negative and positive magnetoresistivity in insulating n-type InP sample in which variable-range hopping occurs at low temperatures. Negative and positive magnetoresistivity associated with variable-range hopping conduction have been observed. Experimental data are tentatively compared with available theoretical models in the insulating regime. [ABSTRACT FROM AUTHOR]

Recently we have shown that by adjusting the thickness of individual sublayers and the nitrogen composition, strain balanced GaAs1-xNx/InAs1-yNy superlattices can be designed to be both lattice matched to InP and have effective bangaps in the desirable 0.4–0.65 eV range. The effect of insertion of such superlattice-like alloy within the intrinsic region of a 0.74 eV InGaAs p-i-n diode was also evaluated and it was shown that such a single junction device exhibits a photovoltaic response comparable to its lattice-mismatched 0.55 eV-InGaAs counterpart. In this work we have extended the approach to multi-junctions devices. Here two or more subcells with different effective bandgaps for the superlattice region are monolithically series connected. Maximum power output and performance of double, triple and quadruple junction TPV cells are evaluated as a function of the superlattice/cell design for a relatively low temperature black body emitters (1350K). The study stresses the potential of the proposed approach for a significant enhancement of TPV converter performance. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Artificial magnetic conductor (AMC) is a kind of periodic structures and it introduces a zero degrees reflection phase shift to incident wave. In order to reduce size of artificial magnetic conductor and increase their working bandwidth, InP process is used to design AMC in this paper. InP material has advantages of large forbidden bandwidth, high electron mobility, negative resistance effect etc. AMC based on InP process has been analyzed and results show that the proposed AMC has a good bandwidth compared with that of CMOS process for its smooth reflection phase variation and its whole size is greatly reduced. [ABSTRACT FROM PUBLISHER]

We present noise temperature and gain measurements of a W-band heterodyne module populated with MMIC LNAs designed and fabricated using a 35 nm InP HEMT process. The module has a WR-10 waveguide input. GPPO connectors are used for the LO input and the I and Q IF outputs. The module is tested at both ambient (300 K) and cryogenic (25 K) temperatures. At 25 K physical temperature, the module has a noise temperature in the range of 27–45 K over the frequency band of 75–111 GHz. The module gain varies between 15 dB and 27 dB. The band-averaged module noise temperature of 350 K and 33 K were measured over 80–110 GHz for the physical temperature of 300 K and 25 K, respectively. The resulting cooling factor is 10.6. [ABSTRACT FROM PUBLISHER]

A differential 50 GSa/s Track and Hold Amplifier with a large bandwidth and a high dynamic range is designed and fabricated with a 320 GHz-Ft-InP-DHBT process. Transient, S-parameters and spectral measurements are presented. For −4 dBm input power, spectral measurements in track mode give a THD and a SFDR of −56.3 dB and −57.3 dB respectively up to 3 GHz and −45.6 dB and −46.2 dB respectively up to 17 GHz. These measured THD are equivalent to 9 and 7.3 ENOB. [ABSTRACT FROM PUBLISHER]

We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure. [ABSTRACT FROM AUTHOR]

We are presenting an overview of InP and GaSb based VCSEL devices in the long-wavelength range. Device structures and performances regarding high-power, tunability and high-speed are discussed by focusing on telecommunication, safety and medical applications. [ABSTRACT FROM PUBLISHER]

We propose and demonstrate a technique cancel common mode signals of sinusoidally gated single photon avalanche diodes (SPADs). This approach enables the elimination of narrow-band filters that fix the frequency of conventional single photon detection with sine wave gating. [ABSTRACT FROM PUBLISHER]

We investigate the generation of THz radiation by the application of ultra-short near-infrared optical pulses to bulk unbiased InP. The THz radiation is detected in the direction of the specular reflection. While the overall emission characteristics are similar to those displayed by InAs under similar excitation conditions, in contrast to InAs, a single-cycle only variation in THz signal, of about ±20%, is observed as the sample is rotated through 360° around the surface normal. [ABSTRACT FROM AUTHOR]

Structural and optical properties of InP films developed with the solutions prepared with InCl3 and Cl2HPO4 salts having different rates by using spraying method have been investigated using the data obtained from UV spectrometer and XRD (x-ray difractometer). Band gap energy values of all samples obtained by using UV spectrometer are found in 1.60–1.85 eV range. It was observed that basic piks of all samples are in (200) plane and have a fcc structure in the XRD analysis. In addition, grain size of the samples increases with the rate of indium included in samples and it is seen that the crystallization in surface structure tends to become more homogenity. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Optically induced nuclear spin polarization is studied via time-resolved magnetooptical Kerr effect in Voigt configuration in n-doped InP. The hyperfine field acting on electrons is detected via a phase shift of the electron spin precession. The dependence of the hyperfine field on external field and the polarization time of the nuclei are discussed within a simple model neglecting nuclear spin diffusion. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

A procedure to etch deep photonic crystal holes in InGaAsP and subsequently fill them with a low index material such as liquid crystal or a solid polymer has been developed. Successful infiltration was proven by optical transmission measurement and in the case of solid polymer also by cross section inspection. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Spin relaxation of electrons doped in InP quantum dots was studied by means of luminescence pump-probe and Hanle measurements. Optical pumping makes spins of doped electrons to be oriented in parallel to the helicity of the circularly polarized excitation. The luminescence pump-probe showed the spin orientation of the doped electrons decay on a millisecond time-scale. Hanle measurement clarified the spin dephasing relaxation time of doped electrons is 1.7 ns which is explained by the frozen fluctuation of nuclear spins. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

We performed structural and electrical investigations on high temperature Fe implanted InP in order to correlate the lattice position of the implanted atoms after annealing treatments to their electrical activation as compensating deep traps. The overall results demonstrate that the Fe2+ deep trap activation properties are strictly connected to the annealing evolution of the lattice location of the Fe atoms in substitutional sites, which in turn is controlled by the background doping density in the substrates. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Electronic and optoelectronic devices based on direct band gap III-V compound semiconductor nanocrystals embedded in Si-based matrices are of great interest due to their compatibility with Si technology. Effective light-emitting properties of III-V semiconductors offer the possibility of integration of different functional optoelectronic devices within a single chip. We present the synthesis of single crystalline InAs, InP and GaAs nanocrystals in SiO2 and silicon using high fluence ion implantation and millisecond flash lamp annealing techniques. The millisecond range processing suppresses the diffusion of the implanted elements what makes the stechiometric nanocrystals formation more effective. The experimental results obtained by means of the high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and optical methods (micro-Raman and photoluminescence spectroscopies) prove formation of high quality nanocrystals of spherical or pyramidal shape. In particular, we have synthesized the inverted crystalline InAs nanopyramids (NPs) at the SiO2/Si interface. The photocurrent and current-voltage measurements confirm the formation of the p-n heterojunction between the p-type silicon substrate and n-type InAs NPs. Similar investigations were successfully performed with InP nanocrystals on Si. The presented results show the usefulness of the ion implantation method followed by flash lamp annealing for the integration of the III-V semiconductors with silicon technology. [ABSTRACT FROM AUTHOR]

The aim of this work, the Hall mobility of InP semiconductor compound which is technologically important material is calculated with iterative method. Furthermore, it is investigated that the calculated values of mobility are depended on temperature interval 30 – 600K and carrier concentrations at 300K. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]