Microscopic Aspects of the Staebler-Wronski Effect

1997 ◽  
Vol 467 ◽  
Author(s):  
Martin Stutzmann
Keyword(s):  
Continuous Wave ◽  
Quantitative Description ◽  
Low Field ◽  
Spin Dependent Transport ◽  
Spin Resonance ◽  
Electron Hole Pair ◽  
Dependent Transport ◽  
Staebler Wronski Effect ◽  
Induced Defects ◽  
Hydrogenated Amorphous

ABSTRACTThe microscopic origin and the creation mechanisms of metastable, light-induced defects in hydrogenated amorphous silicon are reviewed. Based on excitonic electron-hole pair recombination, a consistent quantitative description of defect creation kinetics can be obtained, including the experimentally observed differences between continuous wave and pulsed illumination as well as the effect of competing recombination pathways in compensated material. High resolution spin resonance spectra obtained by low-field spin-dependent transport are used to examine the interaction of metastable defects with hydrogen.

Hydrogen Collision Model of The Staebler-Wronski Effect: Microscopics and Kinetics

1998 ◽  
Vol 507 ◽  
Author(s):  
Howard M. Branz
Keyword(s):  
Room Temperature ◽  
Pair Creation ◽  
Hole Pair ◽  
Dangling Bond ◽  
Electron Hole ◽  
Spin Resonance ◽  
Electron Hole Pair ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous ◽  
Creation Rate

ABSTRACTA new microscopic and kinetic model of light-induced metastability in hydrogenated amorphous silicon (a-Si:H) is described. Recombination and trapping of photoinduced carriers excite hydrogen from deep Si-H bonds into a mobile configuration, leaving a dangling bond (DB) defect at the site of excitation. Normally, mobile H are recaptured at DB defects and no metastability or net DB production results. However, when two mobile H collide, they form a metastable two-hydrogen complex and leave two spatially-uncorrelated Staebler-Wronski DBs. Thermal and light-induced annealing occur when mobile H are excited from the metastable two-H complex; they diffuse and are recaptured to DBs. The microscopic model is entirely compatible with electron-spin-resonance results showing neither DB-DB nor DB-H spatial correlation of the light-induced DBs. The model leads to new differential equations describing the evolution of the mobile H and DB densities. These equation equations explain the observed room-temperature Ndb∼G2/3t1/3 dependence of DB creation upon the electron-hole pair creation rate (G) and time. The model also accounts for both t1/3-kinetics at 4.2K and t1/2-kinetics under laser-pulse soaking. Neither of these results can be explained within the prevailing electron-hole pair recombination model.

Contributions of D0 and non-D0 Gap States to the Kinetics of Light Induced Degradation of Amorphous Silicon under 1 sun Illumination

2001 ◽  
Vol 664 ◽  
Author(s):  
J. Pearce ◽  
X. Niu ◽  
R. Koval ◽  
G. Ganguly ◽  
D. Carlson ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Degradation Kinetics ◽  
Hydrogen Dilution ◽  
Spin Resonance ◽  
The Creation ◽  
Staebler Wronski Effect ◽  
Gap States ◽  
Induced Changes ◽  
Induced Defects ◽  
Hydrogenated Amorphous

ABSTRACTLight induced changes to 1 sun degraded steady state (DSS) have been investigated on hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells and corresponding films fabricated with and without hydrogen dilution of silane. Striking similarities are found for the degradation kinetics, between the electron mobility lifetime (μτ) products and the corresponding fill factors (FF). These correlations that exist for both intrinsic materials at temperatures between 25 and 100°C, are present for the DSS as well as in the kinetics, which exihibit distinctly different dependence on temperature. No such correlations are present between μτ, FF and densities of D0 defects, measured with subgap absorption α(E) at 1.2eV, and electron spin resonance (ESR). The creation of non-D0 defects is also clearly indicated by the temperature dependence of the kinetics and the changes in the shape of α(E) with the results suggesting the presence of more than one mechanism for the creation of light induced defects associated with the Staebler-Wronski effect (SWE).

Bias voltage-dependent low field spin transport properties of Fe3O4–PEG with different particle sizes

2016 ◽  
Vol 30 (23) ◽  
pp. 1650301
Author(s):  
Chunlong Xu ◽  
Zhen Wang ◽  
Lei Wang ◽  
Gang Shi ◽  
Zhaoyang Hou ◽  
...  
Keyword(s):  
Transport Properties ◽  
Bias Voltage ◽  
Room Temperature ◽  
Spin Transport ◽  
Tunneling Effect ◽  
Particle Sizes ◽  
Low Field ◽  
Spin Dependent Transport ◽  
Voltage Dependent ◽  
Dependent Transport

Spin-dependent transport properties of Fe3O4 spheres with diameters from 200 nm to 900 nm have been investigated and polyethylene glycol (PEG) exists on the surface of Fe3O4 particles. The nonlinear I–V curve became obvious with the increase of Fe3O4 diameter, which indicated the tunneling barrier height decreases with the increasing diameter. The magnetoresistance (MR) can reach −13% with an applied low field of 0.2 T at room temperature. With the diameter increase, the MR decreases and the required applied field increases. Moreover, the decrease of MR with the bias voltage increase can be attributed to the spin-dependent tunneling effect through the insulating surface layer of Fe3O4 and PEG.

Tritium Induced Defects in Amorphous Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Whitaker ◽  
J. Viner ◽  
S. Zukotynski ◽  
E. Johnson ◽  
P.C. Taylor ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Defect Production ◽  
Photothermal Deflection Spectroscopy ◽  
Spin Resonance ◽  
Photothermal Deflection ◽  
Induced Defects ◽  
Hydrogenated Amorphous ◽  
Accumulation Of Defects ◽  
Insight Into

ABSTRACTWe report the growth of tritium induced defects in tritium doped hydrogenated amorphous silicon (a-Si:H,T) as measured by electron spin resonance (ESR) and photothermal deflection spectroscopy (PDS). The measurements allow one to examine the accumulation of defects in a-Si:H,T where the defect production mechanism is known. Defects produced by tritium decay are found to be much less numerous than the number of decayed tritium atoms and they are metastable like Staebler-Wronski defects. These results provide new insight into the metastable defect creation and the role of hydrogen motion.

The Enhanced Magnetoresistance Effect of La0.67Sr0.33MnO3 with Pentavalent Ions Addition

2011 ◽  
Vol 675-677 ◽  
pp. 1105-1108
Author(s):  
Bao Xin Huang ◽  
Jun Hua Wang ◽  
Zhen Hua Wang ◽  
Ke Zheng Chen ◽  
Yi Hua Liu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molar Ratio ◽  
Second Phase ◽  
Doping Amount ◽  
Low Field ◽  
Spin Dependent Transport ◽  
Nb Dopant ◽  
Mr Effect ◽  
Dependent Transport ◽  
Calcined Temperature

The magnetic and electrical properties of La0.67Sr0.33MnO3 ( LSMO ) are influenced very much by the Nb dopant. However, this doping effect is restricted by the limited Nb solution into LSMO due to the low calcined temperature. As a result, a second phase LaNbO4 appears in our samples. Enhancements of the low-field magnetoresistance (LFMR) were observed both at 77 K and room temperature in the manganite system prepared by doping Nb2O5 into LSMO powders. The doping amount x of Nb ions ranges from 0-10 % molar ratio. The MR ratios at 77 K with H = 1 T and H = 0.1 T are 33.8 % and 24 % for the x = 0.07 doped sample, respectively. A MR effect up to 9 % was also found for the sample with x = 0.05 at room temperature, which is 2.2 times as large as that for LSMO (4.1%). The spin dependent tunneling and scattering at the interfaces of the grain boundaries are responsible for the LFMR while the high field magnetoresistance (HFMR) originates from the spin dependent transport related to noncollinear spin structure at the interfaces.

Spin-Dependent Transport in GaN Light Emitting Diodes

1995 ◽  
Vol 395 ◽  
Author(s):  
M. S. Brandt ◽  
N. M. Reinacher ◽  
O. Ambacher ◽  
M. Stutzmann
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Spin Dependent Transport ◽  
Spin Resonance ◽  
Recombination Processes ◽  
Electrically Detected Magnetic Resonance ◽  
Dependent Transport ◽  
Heterostructure Devices

ABSTRACTElectrically detected magnetic resonance (EDMR) is used to study recombination processes in two types of gallium nitride light emitting diodes: in m/i/n/n+- and InGaN/AlGaN double-heterostructure devices. In the MIS-diodes, two resonances at g=1.96 and 2.00, corresponding to the effective mass donor and a deep defect are observed at room temperature. At low temperatures, an acceptor-related resonance at g=2.06 is visible as well. After current degradation, the spectra are dominated by the defect resonance, indicating that the creation of this defect is responsible for the decreased electroluminescence efficiency. In the double-heterostrucrure devices, EDMR can only be observed below 60 K showing the g=2.00 defect resonance. The same defect resonance is also observed in conventional electron spin resonance experiments under illumination (light-induced ESR).

Photo-Induced Excess Conductivity in Doping Modulated Amorphous Semiconductors

1985 ◽  
Vol 49 ◽  
Author(s):  
J. Kakalios ◽  
H. Fritzsche
Keyword(s):  
Amorphous Semiconductors ◽  
Excess Conductivity ◽  
Electron Hole ◽  
In Doping ◽  
Pair Separation ◽  
Electron Hole Pair ◽  
Long Life ◽  
Staebler Wronski Effect ◽  
P Type ◽  
Hydrogenated Amorphous

AbstractThe metastable excess conductivity σ(E) observed in hydrogenated amorphous silicon (a-Si:H), that is alternately doped n- and p- type, is compared with the Staebler-Wronski effect and other metastable conductivity changes observed in compensated a-Si:H and in oxidized p- type a-Si:H respectively. We find that Dohler's model of electron-hole pair separation in the pn-junction fields cannot account for the long life of a(E) near and above 300ºK. A defect complex associated with boron having a large configurational relaxation after releasing an electron by photoexcitation is considered as an explanation for σ(E).

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

Sign in / Sign up

Export Citation Format

Share Document