The Role of Charged Defects in Photo-Degradation of Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
Vikram L. Dalal ◽  
Sanjiv Chopra ◽  
Ralph Knox

ABSTRACTWe examine the role of charged defects in inducing degradation of electronic properties of a-Si:H upon exposure to light. We measure the kinetics of decay of photo-conductivity of a-Si:H films at different light intensities, and the corresponding changes in mid-gap optical absorption. We find that the initial, rapid decay of photo-conductivity can be modeled guite well by invoking Adler's model of conversion of charged defects to neutral dangling bonds(D- to D° conversion). A consequence of this conversion is a decrease in sub-gap absorption upon photo-induced degradation, which we observe. Therefore, we conclude that charged defects coexist with neutral defects in a-Si:H, and they play a major role in early stages of photo-degradation.

1985 ◽  
Vol 49 ◽  
Author(s):  
Martin Stutzmann ◽  
Warren B. Jackson ◽  
Chuang Chuang Tsai

AbstractThe dependence of the creation and the annealing of metastable dangling bonds in hydrogenated amorphous silicon on various material parameters will be discussed in the context of a recently proposed model. After a brief review of the kinetic behaviour governing defect creation and annealing in undoped a- Si:H, a number of special cases will be analyzed: the influence of alloying with O, N, C, and Ge, changes introduced by doping and compensation, and the role of mechanical stress. Finally, possibilities to increase the stability of a-Si:H based devices will be examined.


1981 ◽  
Vol 52 (12) ◽  
pp. 7275-7280 ◽  
Author(s):  
Shunri Oda ◽  
Keishi Saito ◽  
Hisashi Tomita ◽  
Isamu Shimizu ◽  
Eiichi Inoue

1992 ◽  
Vol 258 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios

ABSTRACTThe room temperature non-radiative efficiency, defined as the ratio of the heat released per absorbed photon for doped and undoped hydrogenated amorphous silicon (a-Si:H) has been measured using photo-pyroelectric spectroscopy (PPES) for photon energies ranging from 2.5 to 1.6 eV. There is a fairly sharp minimum in the non-radiative efficiency when the a-Si:H is illuminated with near bandgap photons. We describe a model wherein this minimum arises from the variation in the amount of heat generated by free carrier thermalization as the incident photon energy is varied, and report measurements of the excitation kinetics of the non-radiative efficiency which support this proposal.


1992 ◽  
Vol 258 ◽  
Author(s):  
Sufi Zafar ◽  
E. A. Schiff

ABSTRACTA model for correlating the observed properties of hydrogenated amorphous silicon (a-Si:H) with the underlying hydrogen microstructure is reviewed. The model provides a unified description of defect equilibration, hydrogen evolution, rehydrogenation and hydrogen diffusion measurements.


RSC Advances ◽  
2017 ◽  
Vol 7 (31) ◽  
pp. 19189-19196 ◽  
Author(s):  
Z. Marvi ◽  
S. Xu ◽  
G. Foroutan ◽  
K. Ostrikov ◽  
I. Levchenko

Physical and chemical mechanisms and role of plasma in the synthesis of hydrogenated amorphous silicon were studied numerically to reveal the key growth processes and, hence, to ensure a higher level of control over the film structure and properties.


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