Band-Tail Absorption in Hydrogenated Amorphous Silicon

1980 ◽  
Vol 44 (11) ◽  
pp. 749-752 ◽  
Author(s):  
Richard S. Crandall
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Band Tail ◽  
Hydrogenated Amorphous

Measurement of band tail widths in hydrogenated amorphous silicon

2002 ◽  
Vol 299-302 ◽  
pp. 585-588 ◽  
Author(s):  
K Rerbal ◽  
J.-N Chazalviel ◽  
F Ozanam ◽  
I Solomon
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Band Tail ◽  
Hydrogenated Amorphous

Inadequacy of the Conventional View of Hydrogenated Amorphous Silicon

1986 ◽  
Vol 70 ◽  
Author(s):  
D. Adler ◽  
M. Silver ◽  
M. P. Shaw ◽  
V. Cannella
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Intrinsic Defect ◽  
Dangling Bond ◽  
Defect States ◽  
Band Tail ◽  
Conventional View ◽  
Substitutional Doping ◽  
Hydrogenated Amorphous ◽  
Basic Experimental Data

ABSTRACTThe conventional view of the electronic structure of hydrogenated amorphous silicon is: (1) the material is characterized by a mobility gap of about 1.8 eV, with exponential band tails due to disorder and deep defect states arising from silicon dangling bonds (T3 centers); (2) substitutional doping occurs because of the formation of chargedimpurity/dangling-bond pairs, e.g. P4+ – T3-, at the substrate temperature; (3) the effective correlation of the T3 center is about 0.4 eV; (4) T3o centers are the predominant recombination center; (5) the three intrinsic ESR signals are due to electrons on T3o centers, electrons in the conduction band tail, and holes in the valence band tail. It is the purpose of this paper to demonstrate that this model is in sharp disagreement with an array of basic experimental data, and much of the evidence presented in its favor is based on self-inconsistent logic. We conclude that it is very likely that large concentrations of charged intrinsic defect pairs are present in all hydrogenated amorphous silicon films.

Low Temperature Kinetics for the Growth and Decay of Band-Tallcarriers and Dangling Bonds in Hydrogenated Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
Niko Schultz ◽  
P.C. Taylor
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Underlying Mechanism ◽  
Total Production ◽  
Dangling Bonds ◽  
Band Tail ◽  
Thermally Activated ◽  
Spin Resonance ◽  
Hydrogenated Amorphous ◽  
Kinetics Of

AbstractIn hydrogenated amorphous silicon (a-Si:H), the kinetics of the light induced production of silicon dangling bonds and long-lived band-tail electrons and holes has been measured at temperatures between 65 and 340 K using light induced electron spin resonance (LESR). Below about 150 K the measurement of Si dangling bonds is masked by the accumulation of long-lived band-tail carriers. The kinetics of the growth and decay of these long-lived, trapped band-tail carriers consists of very fast components (τ < ms) and very long components (τ > h). Optical quenching of these long-lived carriers is not efficient at quenching energies of 0.6 eV. Afler removal of these long-lived band tail carriers by annealing at about 250 K we find that the total production of silicon dangling bonds at 65 K after 10 h of illumination is about a factor of five less than at 340 K. The dangling bond production resulting from 10 h of illumination is well fit to an underlying mechanism that, if thermally activated, exhibits an activation energy of approximately 10 meV.

Ultrafast Dynamics of Photoexcitations in HWCVD Hydrogenated Amorphous Silicon Alloys

2000 ◽  
Vol 609 ◽  
Author(s):  
J.E. Young ◽  
B.P. Nelson ◽  
S.L. Dexheimer
Keyword(s):  
Amorphous Silicon ◽  
Pump Pulse ◽  
Strong Dependence ◽  
Hydrogenated Amorphous Silicon ◽  
Excitation Density ◽  
Band Tail ◽  
Silicon Alloys ◽  
Bimolecular Recombination ◽  
Extended States ◽  
Hydrogenated Amorphous

ABSTRACTWe present femtosecond studies of carrier dynamics in hydrogenated amorphous silicon-germanium alloys grown by the recently developed hot-wire assisted chemical vapor deposition (HWCVD) technique, which is promising for producing high-quality device-grade materials. We have used wavelength-resolved femtosecond pump-probe techniques, in which an intense pump pulse excites carriers in the sample and a time-delayed probe pulse measures the resulting change in optical properties as a function of time delay following the pump pulse, to study the dynamics of photoexcitations in these materials. Femtosecond dynamics measurements have been carried out on thin film samples under experimental conditions with varying sensitivity to carriers in extended states or in band tail states. The relaxation dynamics of carriers associated with extended states show a strong dependence on excitation density and follow a bimolecular recombination law, consistent with a number of earlier studies on related amorphous materials. In contrast, measurements involving carriers excited directly into band tail states reveal significantly altered dynamics, characterized by a marked deviation from simple bimolecular recombination at short times.

Capacitance Studies of Light-Induced Effects in Undoped Hydrogenated Amorphous Silicon

1985 ◽  
Vol 49 ◽  
Author(s):  
K. Zellama ◽  
J.D. Cohen ◽  
J.P. Harbison
Keyword(s):  
Electrical Conductivity ◽  
Amorphous Silicon ◽  
Density Of States ◽  
Hydrogenated Amorphous Silicon ◽  
Dangling Bond ◽  
Light Saturation ◽  
Band Tail ◽  
Bond Density ◽  
Induced Changes ◽  
Hydrogenated Amorphous

AbstractThe effects of light saturation on the properties of undoped a-Si:H films were studied by a new capacitance profiling technique which can be used to directly determine changes in the dangling bond density of states near midgap. Coplanar conductivity and capacitance vs. temperature measurements save the changes in activation energies for electrical conductivity. These studies indicate that, while substantial increases in the dangling bond densities are observed for most samples, the detailed behavior of the light induced changes in these films are inconsistent with the creation of such defects by breaking weak valence band tail states.

Band-tail photoluminescence in hydrogenated amorphous silicon oxynitride and silicon nitride films

2003 ◽  
Vol 93 (1) ◽  
pp. 239-244 ◽  
Author(s):  
Hiromitsu Kato ◽  
Norihide Kashio ◽  
Yoshimichi Ohki ◽  
Kwang Soo Seol ◽  
Takashi Noma
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Oxynitride ◽  
Band Tail ◽  
Silicon Nitride Films ◽  
Hydrogenated Amorphous
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