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Gas Phase Chemical Detection with an Integrated Chemical Analysis System

Description: Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample concentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is descr… more
Date: July 8, 1999
Creator: Baca, Albert G.; Casalnuovo, Stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Susan L.; Hietala, Vincent M. et al.
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Partner: UNT Libraries Government Documents Department
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InGaAsN/AlGaAs Pnp Heterojunction Bipolar Transistor

Description: The authors have demonstrated a functional Pnp heterojunction bipolar transistor (HBT) using InGaAsN. The metalorganic vapor phase epitaxy (MOCVD) grown Al{sub 0.3}Ga{sub 0.7}As/In{sub 0.03}Ga{sub 0.97}As{sub 0.99}N{sub 0.01} HBT takes advantage of the narrower bandgap energy (E{sub g} = 1.25eV) of In{sub 0.03}Ga{sub 0.97}As{sub 0.99}N{sub 0.01}, which is lattice matched to GaAs. Compared with the Al{sub 0.3}Ga{sub 0.7}As/GaAs material system, the Al{sub 0.3}Ga{sub 0.7}As/In{sub 0.03}Ga{sub 0.9… more
Date: November 3, 1999
Creator: Baca, Albert G.; Chang, Ping-Chih; Hou, H. Q.; Laroche, J. R.; Li, N. Y.; Ren, F. et al.
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Partner: UNT Libraries Government Documents Department
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Materials physics and device development for improved efficiency of GaN HEMT high power amplifiers.

Description: GaN-based microwave power amplifiers have been identified as critical components in Sandia's next generation micro-Synthetic-Aperture-Radar (SAR) operating at X-band and Ku-band (10-18 GHz). To miniaturize SAR, GaN-based amplifiers are necessary to replace bulky traveling wave tubes. Specifically, for micro-SAR development, highly reliable GaN high electron mobility transistors (HEMTs), which have delivered a factor of 10 times improvement in power performance compared to GaAs, need to be devel… more
Date: December 1, 2005
Creator: Kurtz, Steven Ross; Follstaedt, David Martin; Wright, Alan Francis; Baca, Albert G.; Briggs, Ronald D.; Provencio, Paula Polyak et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Novel Metal-Sulfur-Based Air-Stable Passivation of GaAs with Very Low Surface State Densities

Description: A new air-stable electronic surface passivation for GaAs and other III-V compound semiconductors that employs sulfur and a suitable metal ion, e.g., Zn, and that is robust towards plasma dielectric deposition has been developed. Initial improvements in photoluminescence are twice that of S-only treatments and have been preserved for >11 months with SiO{sub x}N{sub y} dielectric encapsulation. Photoluminescence and X-ray photoelectron spectroscopies indicate that the passivation consists of t… more
Date: August 9, 1999
Creator: Ashby, Carol I.H.; Baca, Albert G.; Chang, P.-C; Hafich, M.J.; Hammons, B.E. & Zavadil, Kevin R.
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Partner: UNT Libraries Government Documents Department
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Transport, Growth Mechanisms, and Material Quality in GaN Epitaxial Lateral Overgrowth

Description: Growth kinetics, mechanisms, and material quality in GaN epitaxial lateral over-growth (ELO) were examined using a single mask of systematically varied patterns. A 2-D gas phase reaction/diffusion model describes how transport of the Ga precursor to the growth surface enhances the lateral rate in the early stages of growth. In agreement with SEM studies of truncated growth runs, the model also predicts the dramatic decrease in the lateral rate that occurs as GaN over-growth reduces the exposed … more
Date: January 11, 1999
Creator: Baca, Albert G.; Bartram, M. E.; Coltrin, M. E.; Crawford, M. H.; Han, J.; Missert, N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Semiconductor e-h plasma lasers

Description: A new type of GaAs laser is based on the electron-hole plasma in a current filament and is not limited in size by p-n junctions. High energy, electrically controlled, compact, short-pulse lasers are useful for: active optical sensors (LADAR, range imaging, imaging through clouds, dust, smoke, or turbid water), direct optical ignition of fuels and explosives, optical recording, and micro-machining. The authors present a new class of semiconductor laser that can potentially produce much more shor… more
Date: June 6, 2000
Creator: Zutavern, Fred J.; Baca, Albert G.; Chow, Weng W.; Hafich, Michael J.; Hjalmarson, Harold P.; Loubriel, Guillermo M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Gas phase chemical detection with an integrated chemical analysis system

Description: Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample preconcentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is de… more
Date: April 12, 2000
Creator: Casalnuovo, Stephen A.; Frye-Mason, Gregory Charles; Kottenstette, Richard; Heller, Edwin J.; Matzke, Carolyn M.; Lewis, Patrick R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Device characteristics of the PnP AlGaAs/InGaAsN/GaAs double heterojunction bipolar transistor

Description: The authors have demonstrated a functional PnP double heterojunction bipolar transistor (DHBT) using AlGaAs, InGaAsN, and GaAs. The band alignment between InGaAsN and GaAs has a large {triangle}E{sub C} and a negligible {triangle}E{sub V}, and this unique characteristic is very suitable for PnP DHBT applications. The metalorganic vapor phase epitaxy (MOCVD) grown Al{sub 0.3}Ga{sub 0.7}As/In{sub 0.03}Ga{sub 0.97}As{sub 0.99}N{sub 0.01}/GaAs PnP DHBT is lattice matched to GaAs and has a peak curr… more
Date: February 9, 2000
Creator: Chang, Ping-Chih; Li, N. Y.; Laroche, J. R.; Baca, Albert G.; Hou, H. Q. & Ren, F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Monolithic integration of GaAs SAW chemical microsensor arrays and detection electronics

Description: The authors describe the integration of an array of surface acoustic wave delay line chemical sensors with the associated RF microelectronics such that the resulting device operates in a DC in/DC out mode. The microelectronics design for on-chip RF generation and detection is presented. Both hybrid and monolithic approaches are discussed. This approach improves system performance, simplifies packaging and assembly, and significantly reduces overall system size. The array design can be readily s… more
Date: April 17, 2000
Creator: Casalnuovo, Stephen A.; Hietala, Vincent M.; Heller, Edwin J.; Ason, Gregory Charles & Baca, Albert G.
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Partner: UNT Libraries Government Documents Department
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Effect of Mg ionization efficiency on performance of Npn AlGaN/GaN heterojunction bipolar transistors

Description: A drift-diffusion transport model has been used to examine the performance capabilities of AlGaN/GaN Npn heterojunction bipolar transistors (HBTs). The Gummel plot from the first GaN-based HBT structure recently demonstrated is adjusted with simulation by using experimental mobility and lifetime reported in the literature. Numerical results have been explored to study the effect of the p-type Mg doping and its incomplete ionization in the base. The high base resistance induced by the deep accep… more
Date: March 10, 2000
Creator: Monier, C.; Pearton, S. J.; Chang, Ping-Chih & Baca, Albert G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of 1.25 eV InGaAsN for triple junction solar cells

Description: Development of next generation high efficiency space monolithic multifunction solar cells will involve the development of new materials lattice matched to GaAs. One promising material is 1.05 eV InGaAsN, to be used in a four junction GaInP{sub 2}/GaAs/InGaAsN/Ge device. The AMO theoretical efficiency of such a device is 38--42%. Development of the 1.05 eV InGaAsN material for photovoltaic applications, however, has been difficult. Low electron mobilities and short minority carrier lifetimes hav… more
Date: May 16, 2000
Creator: Li, N. Y.; Sharps, P. R.; Hills, J. S.; Hou, H.; Chang, Ping-Chih & Baca, Albert G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Aluminum-Free P-n-P InGaAsN Double Heterojunction Bipolar Transistors

Description: The authors have demonstrated an aluminum-free P-n-P GaAs/InGaAsN/GaAs double heterojunction bipolar transistor (DHBT). The device has a low turn-on voltage (V{sub ON}) that is 0.27 V lower than in a comparable P-n-p AlGaAs/GaAs HBT. The device shows near-ideal D. C. characteristics with a current gain ({beta}) greater than 45. The high-speed performance of the device are comparable to a similar P-n-p AlGaAs/GaAs HBT, with f{sub T} and f{sub MAX} values of 12 GHz and 10 GHz, respectively. This … more
Date: August 1, 2000
Creator: Chang, Ping-Chih; Li, N. Y.; Baca, Albert G.; Monier, C.; Laroche, J. R.; Hou, H. Q. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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GaN High Power Devices

Description: A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers, GaN/AlGaN heterojunction bipolar transistors, GaN heterostructure and metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.
Date: July 17, 2000
Creator: Pearton, S. J.; Ren, F.; Zhang, A. P.; Dang, G.; Cao, X. A.; Lee, K. P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Role of defects in III-nitride based electronics

Description: The LDRD entitled ``Role of Defects in III-Nitride Based Devices'' is aimed to place Sandia National Laboratory at the forefront of the field of GaN materials and devices by establishing a scientific foundation in areas such as material growth, defect characterization/modeling, and processing (metalization and etching) chemistry. In this SAND report the authors summarize their studies such as (1) the MOCVD growth and doping of GaN and AlGaN, (2) the characterization and modeling of hydrogen in … more
Date: January 1, 2000
Creator: Han, Jung; Myers, Samuel M., Jr.; Follstaedt, David M.; Wright, Alan F.; Crawford, Mary H.; Lee, Stephen R. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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AlGaAs/InGaAlP tunnel junctions for multijunction solar cells

Description: Optimization of GaInP{sub 2}/GaAs dual and GaInP{sub 2}/GaAs/Ge triple junction cells, and development of future generation monolithic multi-junction cells will involve the development of suitable high bandgap tunnel junctions. There are three criteria that a tunnel junction must meet. First, the resistance of the junction must be kept low enough so that the series resistance of the overall device is not increased. For AMO, 1 sun operation, the tunnel junction resistance should be below 5 x 10{… more
Date: May 16, 2000
Creator: Sharps, P. R.; Li, N. Y.; Hills, J. S.; Hou, H.; Chang, Ping-Chih & Baca, Albert G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The development of integrated chemical microsensors in GaAs

Description: Monolithic, integrated acoustic wave chemical microsensors are being developed on gallium arsenide (GaAs) substrates. With this approach, arrays of microsensors and the high frequency electronic components needed to operate them reside on a single substrate, increasing the range of detectable analytes, reducing overall system size, minimizing systematic errors, and simplifying assembly and packaging. GaAs is employed because it is both piezoelectric, a property required to produce the acoustic … more
Date: November 1, 1999
Creator: Casalnuvo, Stephen A.; Ason, Gregory Charles; Heller, Edwin J.; Hietala, Vincent M.; Baca, Albert G. & Hietala, S. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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GaN Electronics For High Power, High Temperature Applications

Description: A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers. GaN/AlGaN heterojunction bipolar transistors and GaN metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.
Date: June 12, 2000
Creator: Pearton, S. J.; Ren, F.; Zhang, A. P.; Dang, G.; Cao, X. A.; Lee, K. P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Acoustic Wave Chemical Microsensors in GaAs

Description: High sensitivity acoustic wave chemical microsensors are being developed on GaAs substrates. These devices take advantage of the piezoelectric properties of GaAs as well as its mature microelectronics fabrication technology and nascent micromachining technology. The design, fabrication, and response of GaAs SAW chemical microsensors are reported. Functional integrated GaAs SAW oscillators, suitable for chemical sensing, have been produced. The integrated oscillator requires 20 mA at 3 VK, opera… more
Date: September 20, 1998
Creator: Baca, Albert G.; Heller, Edwin J.; Frye-Mason, Gregory C.; Reno, John L.; Kottenstette, Richard; Casalnuovo, Stephen A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inductively Coupled Plasma-Induced Etch Damage of GaN p-n Junctions

Description: Plasma-induced etch damage can degrade the electrical and optical performance of III-V nitride electronic and photonic devices. We have investigated the etch-induced damage of an Inductively Coupled Plasma (ICP) etch system on the electrical performance of mesa-isolated GaN pn-junction diodes. GaN p-i-n mesa diodes were formed by Cl{sub 2}/BCl{sub 3}/Ar ICP etching under different plasma conditions. The reverse leakage current in the mesa diodes showed a strong relationship to chamber pressure,… more
Date: November 3, 1999
Creator: Shul, Randy J.; Zhang, Lei; Baca, Albert G.; Willison, Christi Lee; Han, Jung; Pearton, S. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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