A Study of Traps in Semi-Insulating III-V Epitaxial Films by Zero Bias Transient Current Spectroscopy

1994 ◽  
Vol 340 ◽  
Author(s):  
W. S. Lau ◽  
C. H. Goo ◽  
T. C. Chong ◽  
C. T. Tan
Keyword(s):  
Activation Energy ◽  
Surface States ◽  
Epitaxial Films ◽  
Electron Trap ◽  
Transient Current ◽  
Hole Trap ◽  
Zero Bias ◽  
Voltage Transient ◽  
Continuum Of States ◽  
The Continuum

ABSTRACTSemi-insulating Al0.3Ga0.7AS epitaxial films grown by molecular beam epitaxy at 400°C have been characterised by a recently proposed technique known as zero quiescent bias voltage transient current spectroscopy (ZBTCS). Separated electron trap spectra and hole trap spectra are obtained by ZBTCS. From these spectra, a prominent hole trap with an activation energy of 1.01eV, a prominent electron trap with an activation energy of 0.86eV and a continuum of states are detected. The trap concentrations of the detected hole trap and electron trap are calculated to be about 3.6x1015cm−3 and 9.7x1015cm−3 respectively. The continuum of states is believed to be due to the surface states of the Al0.3Ga0.7AS film. By passivating the surface with (NH4)2S solution, the magnitudes of the continuums in the spectra reduce significantly. With the reduction of the surface states, hole injections that interfere the electron trap spectra are suppressed, and consequently electron trap spectra with more pronounced peaks are produced.

Optical Degradation and Morphology in a-Si:H

1989 ◽  
Vol 149 ◽  
Author(s):  
Jun-ichi Nakata ◽  
Atsushi Miyanishi ◽  
Junji Shirafuji ◽  
Shozo Imao ◽  
Keiji Fujibayashi ◽  
...  
Keyword(s):  
Activation Energy ◽  
Hydrogen Diffusion ◽  
Hydrogenated Amorphous Silicon ◽  
Electron Trap ◽  
Simultaneous Increase ◽  
Hole Trap ◽  
Dangling Bonds ◽  
Higher Temperature ◽  
The Relationship ◽  
Hydrogenated Amorphous

ABSTRACTThe relationship between the optical degradation and the morphology of hydrogenated amorphous silicon (a-Si:H) films was studied through the analysis of the annealing processes. The annealing of optically induced metastable dangling bonds can be explained in terms of the first and the second order reactions with dispersive hydrogen diffusion for the films deposited at lower and higher temperature, respectively. The activation energy of the annealing was estimated to be 0.8 eV with a small distribution in both cases. Optically enhanced annealing was first observed. It was found by DLTS and CT measurements that the density of hole trap located at Ev+0.6 eV was remarkably decreased by the light soaking, accompanied by the simultaneous increase of electron trap at Ec-0.7 ∼ Ec-0.9 eV due to the dangling bonds. These experimental facts support the view that the hole trap corresponds to the weak bonds, which convert to the metastable dangling bonds by light soaking.

scholarly journals Signature of a pair of Majorana zero modes in superconducting gold surface states

2020 ◽  
Vol 117 (16) ◽  
pp. 8775-8782 ◽  
Author(s):  
Sujit Manna ◽  
Peng Wei ◽  
Yingming Xie ◽  
Kam Tuen Law ◽  
Patrick A. Lee ◽  
...  
Keyword(s):  
Surface States ◽  
Gold Surface ◽  
Building Blocks ◽  
Energy Scale ◽  
Scanning Tunneling ◽  
Tunneling Conductance ◽  
Gold Nanowires ◽  
Noise Sources ◽  
Zero Bias ◽  
Zero Modes

Under certain conditions, a fermion in a superconductor can separate in space into two parts known as Majorana zero modes, which are immune to decoherence from local noise sources and are attractive building blocks for quantum computers. Promising experimental progress has been made to demonstrate Majorana zero modes in materials with strong spin–orbit coupling proximity coupled to superconductors. Here we report signatures of Majorana zero modes in a material platform utilizing the surface states of gold. Using scanning tunneling microscope to probe EuS islands grown on top of gold nanowires, we observe two well-separated zero-bias tunneling conductance peaks aligned along the direction of the applied magnetic field, as expected for a pair of Majorana zero modes. This platform has the advantage of having a robust energy scale and the possibility of realizing complex designs using lithographic methods.

DLTS studies of defects produced in n-type silicon by hydrogen implantation at low temperature

2002 ◽  
Vol 744 ◽  
Author(s):  
Takahide Sugiyama ◽  
Masayasu Ishiko ◽  
Shigeki Kanazawa ◽  
Yutaka Tokuda
Keyword(s):  
Activation Energy ◽  
Low Temperature ◽  
Room Temperature ◽  
Reverse Bias ◽  
Thermal Emission ◽  
Sample Temperature ◽  
Zero Bias ◽  
Type Silicon ◽  
Projected Range ◽  
Hydrogen Implantation

ABSTRACTMetastable defects are discovered in hydrogen-implanted n-type silicon. Hydrogen implantation was performed with the energy of 80 keV to a dose of 2×10 cm- at 109 K. After implantation, the sample temperature was raised to room temperature. DLTS measurements were carried out in the temperature range 80–290 K for fabricated diodes. When the sample is reverse-biased at 10V for 10 min at room temperature and then is cooled down to 80 K, three new peaks labeled EM1, EM2 and EM3 appear around 150, 190 and 240 K, respectively. The introduction of metastable defects is found to be characteristic of low temperature implantation. We have evaluated properties of EM1 in detail. EM1 with thermal emission activation energy of 0.29 eV has a peak in concentration around the depth of 0.64 μ m, which corresponds to the projected range of 80 keV hydrogen. EM1 is regenerated with the reverse bias applied around 270 K and is removed with the zero bias around 220 K.

Dislocations and Traps in MBE Grown Lattice Mismatched p- InGaAs/GaAs Layers on GaAs Substrates

1997 ◽  
Vol 484 ◽  
Author(s):  
A. Y. Du ◽  
M. F. Li ◽  
T. C. Chong ◽  
Z. Zhang
Keyword(s):  
Activation Energy ◽  
Layer Thickness ◽  
Deep Level ◽  
Photo Luminescence ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Trap Level ◽  
Nonradiative Recombination ◽  
Hole Trap ◽  
Transient Spectroscopy

AbstractDislocations and traps in MBE grown p-InGaAs/GaAs lattice-mismatched heterostructures are investigated by Cross-section Transmission Electron Microscopy (XTEM), Deep Level Transient Spectroscopy (DLTS) and Photo-luminescence (PL). The misfit dislocations and the threading dislocations observed by XTEM in different samples with different In mole fractions and different InGaAs layer thickness generally satisfy the Dodson-Tsao's plastic flow critical layer thickness curve. The threading dislocations in bulk layers introduce three hole trap levels HI, H2 and H5 with DLTS activation energies of 0.32 eV, 0.40 eV, 0.88 eV, respectively, and one electron trap El with DLTS activation energy of 0.54 eV. The misfit dislocations in relaxed InGaAs/GaAs interface induce a hole trap level H4 with DLTS activation energy between the range of 0.67–0.73 eV. All dislocation induced traps are nonradiative recombination centers which greatly degrade the optical property of the InGaAs/GaAs layers.

Role of Mesoporous TiO2 Surface States and Metal Oxide Treatment on Charge Transport of Dye Sensitized Solar Cells

2010 ◽  
Vol 1270 ◽  
Author(s):  
Mariyappan Shanmugam ◽  
Braden Bills ◽  
Mahdi Farrokh Baroughi
Keyword(s):  
Activation Energy ◽  
Dark Current ◽  
Hafnium Oxide ◽  
Photovoltaic Performance ◽  
Dye Sensitized Solar Cells ◽  
Surface States ◽  
Atomic Layer ◽  
Dye Sensitized ◽  
Layer Deposition ◽  
Atomic Layer Deposition Method

AbstractPhotovoltaic performance of dye sensitized solar cell (DSSC) was enhanced by 19 and 69 % compared to untreated DSSC by treating the nanoporous titanium dioxide (TiO2) by ultra thin Aluminum oxide (Al2O3) and Hafnium oxide (HfO2) grown by atomic layer deposition method. Activation energy of dark current, obtained from the temperature dependent current-voltage (I-V-T), of the untreated DSSC was 1.03 eV on the other hand the DSSCs with Al2O3 and HfO2 surface treatment showed 1.27 and 1.31 eV respectively. A significant change in the activation energy of dark current, over 0.24 eV for Al2O3 treatment and 0.28 eV in case of HfO2 treatment, suggest that density and activity of surface states on nanoporous TiO2 was suppressed by ALD grown metal oxides to result improved photovoltaic performance. Further the enhanced DSSC performance was confirmed by external quantum efficiency measurement in the wavelength range of 350-750 nm.

Influence of Oxygen and Boron on Defect Production in Irradiated Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
P. J. Drevinsky ◽  
C. E. Caefer ◽  
S. P. Tobin ◽  
J. C. Mikkelsen ◽  
L. C. Kimerling
Keyword(s):  
Carbon Content ◽  
Oxygen Content ◽  
Boron Concentration ◽  
Electron Trap ◽  
Hole Trap ◽  
Defect Production ◽  
Interstitial Defects ◽  
Defect Reactions ◽  
P Type ◽  
Initial Results

ABSTRACTIntroduction rates of dominant defects have been determined for electron-irradiated, p-type silicon as a function of oxygen and boron concentration. Samples included those with oxygen content ranging from 8 × 1015 to 7 × 1017 cm−3. Initial results are described for samples with measured carbon content varying from 2 × 1015 to 6 × 1016 cm−3. Competing defect reactions involving the interstitial defects, Bi and Ci, and oxygen, boron, and carbon are observed. The identities of an electron trap (Bi-Oi) and a hole trap (Bi-Bs) have been clarified.

Electron-Trap and Hole-Trap Distributions in Metal/Oxide/Nitride/Oxide/Silicon Structures

2013 ◽  
Vol 60 (2) ◽  
pp. 863-869 ◽  
Author(s):  
Takeshi Ishida ◽  
Toshiyuki Mine ◽  
Digh Hisamoto ◽  
Yasuhiro Shimamoto ◽  
Ren-ichi Yamada
Keyword(s):  
Metal Oxide ◽  
Electron Trap ◽  
Hole Trap ◽  
Silicon Structures ◽  
Nitride Oxide

scholarly journals Tamm–Hubbard surface states in the continuum

2013 ◽  
Vol 25 (23) ◽  
pp. 235601 ◽  
Author(s):  
S Longhi ◽  
G Della Valle
Keyword(s):  
Surface States ◽  
The Continuum
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