Comparison of Current-Induced Migration of Be and C in GaAs/AlGaAs HBTs

1992 ◽  
Vol 262 ◽  
Author(s):  
F. Ren ◽  
T. R. Fullowan ◽  
J. R. Lothian ◽  
P. W. Wisk ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Current Density ◽  
Ideality Factor ◽  
Current Gain ◽  
Rapid Degradation ◽  
Enhanced Diffusion ◽  
Aging Conditions ◽  
The Stability ◽  
Dc Current ◽  
A Current ◽  
Base Doping

ABSTRACTWe contrast the stability under bias-aging conditions of GaAs/AlGaAs HBTs utilizing highly Be- or C-doped base layers. Devices with Be doping display a rapid degradation of dc current gain and junction ideality factor. At 200°C, a 2 × 10 μm2 Be-doped device (4 × 1019cm−3 base doping) operated at a current density of 2.5 × 104 A. cm−2 shows a decrease in gain from 16 to 1.5 within 2h. Under the same conditions a C-doped device with even higher base-doping (7 × 1019 cm−3) is stable over periods of 36h, the longest time we tested our structures. The degradation of Be-doped devices is consistent with the mechanism of recombination-enhanced diffusion of interstitials into the adjoining layers. Similar results are obtained with Zn-doped devices. Since C occupies the As sub-lattice rather than the Ga sublattice as with Be and Zn, it is not susceptible to reaction with Ga interstitials injected during growth or bias-aging.

scholarly journals The Effect of Cu Ohmic Contact on Photoelectrochemical Property of S-CuO Thin Film Photocathodes

2019 ◽  
Vol 22 (6) ◽  
pp. 255-262
Author(s):  
Aziz Amrullah ◽  
Gunawan Gunawan ◽  
Nor Basid Adiwibawa Prasetya
Keyword(s):  
Thin Film ◽  
Current Density ◽  
Ohmic Contact ◽  
Photoelectrochemical Properties ◽  
Photoelectrochemical Property ◽  
Onset Potential ◽  
Best Response ◽  
Cyclic Voltammetry Method ◽  
The Stability ◽  
A Current

The development of semiconductor materials as photocathodes that have excellent performance is significant for the photoelectrochemical reaction of hydrogen evolution. The thin film of sulfur-doped Copper (II) oxide (S-CuO)  was successfully synthesized using the cyclic voltammetry method. Investigation of photoelectrochemical properties of S-CuO photocathodes, including current density, onset potential, applied photon to current efficiency (ABPE), and bandgap had been carried out. It was reported that the Cu ohmic contact affected the photoelectrochemical properties and the stability of the thin film. The presence of Cu ohmic contact can improve the performance of S-CuO thin film photocathodes. The S-CuO TU 20 mM thin film has the best response with a current density of -0.923 mA/cm2, an onset potential of 0.59 V, and ABPE of 0.21%. Stability occurred at pH 7 in 0.2M NaH2PO4. The optical analysis showed S-CuO TU 20 mM bandgap of 1.7 eV.

scholarly journals The Effect of Cu Ohmic Contact on Photoelectrochemical Property of S-CuO Thin Film Photocathodes

2019 ◽  
Vol 22 (6) ◽  
pp. 256-262 ◽  
Author(s):  
Aziz Amrullah ◽  
Gunawan Gunawan ◽  
Nor Basid Adiwibawa Prasetya
Keyword(s):  
Thin Film ◽  
Current Density ◽  
Ohmic Contact ◽  
Photoelectrochemical Properties ◽  
Photoelectrochemical Property ◽  
Onset Potential ◽  
Best Response ◽  
Cyclic Voltammetry Method ◽  
The Stability ◽  
A Current

The development of semiconductor materials as photocathodes that have excellent performance is significant for the photoelectrochemical reaction of hydrogen evolution. The thin film of sulfur-doped Copper (II) oxide (S-CuO)  was successfully synthesized using the cyclic voltammetry method. Investigation of photoelectrochemical properties of S-CuO photocathodes, including current density, onset potential, applied photon to current efficiency (ABPE), and bandgap had been carried out. It was reported that the Cu ohmic contact affected the photoelectrochemical properties and the stability of the thin film. The presence of Cu ohmic contact can improve the performance of S-CuO thin film photocathodes. The S-CuO TU 20 mM thin film has the best response with a current density of -0.923 mA/cm2, an onset potential of 0.59 V, and ABPE of 0.21%. Stability occurred at pH 7 in 0.2M NaH2PO4. The optical analysis showed S-CuO TU 20 mM bandgap of 1.7 eV.

4H-SiC Bipolar Junction Transistors with Graded Base Doping Profile

2009 ◽  
Vol 615-617 ◽  
pp. 829-832 ◽  
Author(s):  
Jian Hui Zhang ◽  
Leonid Fursin ◽  
Xue Qing Li ◽  
Xiao Hui Wang ◽  
Jian Hui Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Vapor ◽  
Doping Profile ◽  
Current Gain ◽  
Bipolar Junction Transistors ◽  
Bipolar Junction Transistor ◽  
Blocking Voltage ◽  
Junction Transistor ◽  
Dc Current ◽  
Base Doping

This work reports 4H-SiC bipolar junction transistor (BJT) results based upon our first intentionally graded base BJT wafer with both base and emitter epi-layers continuously grown in the same reactor. The 4H-SiC BJTs were designed to improve the common emitter current gain through the built-in electrical fields originating from the grading of the base doping. Continuously-grown epi-layers are also believed to be the key to increasing carrier lifetime and high current gains. The 4H-SiC BJT wafer was grown in an Aixtron/Epigress VP508, a horizontal hot-wall chemical vapor deposition reactor using standard silane/propane chemistry and nitrogen and aluminum dopants. High performance 4H-SiC BJTs based on this initial non-optimized graded base doping have been demonstrated, including a 4H-SiC BJT with a DC current gain of ~33, specific on-resistance of 2.9 mcm2, and blocking voltage VCEO of over 1000 V.

scholarly journals Design of a Single-Ion Conducting Polymer Electrolyte for Sodium-Ion Batteries

2021 ◽  
Author(s):  
Kewei Liu ◽  
Yingying Xie ◽  
Zhenzhen Yang ◽  
Hong-Keun Kim ◽  
Trevor Dzwiniel ◽  
...  
Keyword(s):  
Polymer Electrolyte ◽  
Current Density ◽  
Specific Capacity ◽  
Transference Number ◽  
Free Standing ◽  
Ion Conducting ◽  
The Stability ◽  
Ion Conducting Polymer ◽  
A Current

Abstract A sodium bis(fluoroallyl)malonato borate salt (NaBFMB) was synthesized. NaBFMB can be photo-crosslinked to create a single-ion conducting electrolyte (NaSIE), with anions immobilized through the 3-D crosslinked network. The NaSIE can be prepared either as a free-standing film or through a drop-cast method followed by a photo crosslinking method for an in-situ formation on top of the electrodes. The free-standing film of NaSIE has a high ionic conductivity of 2×10-3 S/cm at 30 oC, and a high transference number (tNa+) of 0.91 . The electrochemical stability of NaSIE polymer electrolyte was demonstrated be stable up to 5 V vs Na/Na+. When tested inside a symmetrical Na//Na cell, the NaSIE shows a critical current density (CCD) of 0.4 mA/cm2. The stability of NaSIE was further demonstrated via a long cycling of the stripping/plating test with a current density of 0.1 mA/cm2 at five-minute intervals for over 10,000 minutes. Using the in-situ method, NaSIE was used as the electrolyte for a sodium metal battery using P2cathode of Na0.67Ni0.33Mn0.67O2 (NNMO) and was cycled between the cut-off voltages of 2.0 – 4.0 V. A high initial specific capacity (85.7 mAh/g) with a capacity retention of 86.79% after 150 cycles was obtained.

scholarly journals Tartrate-Based Electrolyte for Electrodeposition of Fe–Sn Alloys

Coatings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 313
Author(s):  
Simona Mrkonjić Zajkoska ◽  
Edmund Dobročka ◽  
Selma Hansal ◽  
Rudolf Mann ◽  
Wolfgang E. G. Hansal ◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
Ph Value ◽  
Complexing Agent ◽  
Lack Of Information ◽  
The Stability ◽  
First Time ◽  
Anomalous Deposition ◽  
Main Attribute ◽  
A Current

Magnetic properties of the sustainable Fe–Sn alloys are already known. However, there is lack of information in the field of Fe–Sn electrodeposition. In the present study, a novel Fe(III)–Sn(II) electrolyte with tartaric acid as a single complexing agent is introduced. The influence of the pH and the current density on the structural properties of the Fe–Sn deposit was studied. The stability of the electrolytes as a main attribute of sustainability was tested. The ferromagnetic phases Fe5Sn3 and Fe3Sn were electrodeposited for the first time, and it was found that the mechanism of the Fe–Sn deposition changes from normal to anomalous at a pH value 3.0 and a current density of approximately 30 mA/cm2. A possible reason for the anomalous deposition of Fe–Sn is the formation of Fe-hydroxides on the cathode surface. Two electrolyte stability windows exist: The first stability window is around a pH value of 1.8 where bimetallic Fe–Sn tartrate complexes were formed, and second one is around a pH value of 3.5 where most of the Sn ions were present in the form of [Sn(tart)2]2− and Fe in the form of [Fe(tart)]+ complexes.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

GaAlAs/GaAs heterojunction bipolar phototransistors grown by LPE with a current gain of 50 000

1985 ◽  
Vol 21 (24) ◽  
pp. 1124 ◽  
Author(s):  
A. Cazarre ◽  
J. Tasselli ◽  
A. Marty ◽  
J.P. Bailbe ◽  
G. Rey
Keyword(s):  
Current Gain ◽  
A Current
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