Critique of (time)1/3kinetics of defect formation in amorphous Si:H and a possible alternative model—Comment on ‘‘Kinetics of the Staebler–Wronski effect in hydrogenated amorphous silicon’’ [Appl. Phys. Lett.45, 1075 (1984)]

1989 ◽  
Vol 54 (4) ◽  
pp. 398-399 ◽  
Author(s):  
David Redfield
Keyword(s):  
Amorphous Silicon ◽  
Alternative Model ◽  
Defect Formation ◽  
Hydrogenated Amorphous Silicon ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous ◽  
Kinetics Of

Magnetic Resonance Probes Of Band Tail States And Defects In Tetrahedrally Coordinated Amorphous Semiconductors

2002 ◽  
Vol 715 ◽  
Author(s):  
P. C. Taylor
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Amorphous Semiconductors ◽  
Dangling Bonds ◽  
Band Tail ◽  
Wide Range ◽  
Recombination Processes ◽  
Staebler Wronski Effect ◽  
Hydrogenated Amorphous ◽  
Kinetics Of

AbstractRecent electron spin resonance (ESR) results relating to (1) recombination processes for optically excited electrons and holes in tetrahedrally coordinated amorphous semiconductors and (2) kinetics of metastable defects (dangling bonds associated with the Staebler-Wronski effect) in hydrogenated amorphous silicon (a-Si:H). With regard to recombination processes, ESR measurements have been performed over a wide range of excitation intensities (nW/cm2 to W/cm2) on hydrogenated amorphous silicon (a-Si:H) and hydrogenated amorphous germanium (a-Ge:H). The kinetics can be studied down to carrier densities as low as 1014 cm-3. The longtime decay curves show that at large carrier separation (1) the random distribution of optically excited electrons and holes is subject to the condition of charge neutrality, and (2) the decays are universal and independent of the densities of localized, band-tail states. With regard to the metastable defects in a-Si:H, the kinetics of the production and thermal annealing of silicon dangling bonds have been measured at temperatures between 25 and 480 K using ESR. Below about 150 K the measurement of the dangling bonds is masked by long-lived, band tail carriers that accumulate with time. The production rate for silicon dangling bonds decreases with decreasing temperature and is nearly temperature independent below approximately 100 K. Defects created by 10 hours of irradiation below 100 K anneal almost completely at 300 K. In a- Ge:H, the first measurements of optically induced, metastable germanium dangling bonds have been made.

The Spectral Dependence of the Non-Radiative Efficiency in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Amorphous Silicon ◽  
Room Temperature ◽  
Hydrogenated Amorphous Silicon ◽  
Free Carrier ◽  
Radiative Efficiency ◽  
Sharp Minimum ◽  
Carrier Thermalization ◽  
Hydrogenated Amorphous ◽  
Kinetics Of ◽  
Heat Released

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.

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