A universal feature in the optical absorption spectrum associated with hydrogenated amorphous silicon: A dimensionless joint density of states analysis

2016 ◽  
Vol 120 (13) ◽  
pp. 135706 ◽  
Author(s):  
Jasmin J. Thevaril ◽  
Stephen K. O'Leary
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Amorphous Silicon ◽  
Density Of States ◽  
Optical Absorption Spectrum ◽  
Hydrogenated Amorphous Silicon ◽  
Joint Density ◽  
Universal Feature ◽  
Hydrogenated Amorphous

Optical Absorption in Amorphous Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
S. K. O'Leary ◽  
S. Zukotynski ◽  
J. M. Perz ◽  
L. S. Sidhu
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Amorphous Silicon ◽  
Optical Absorption Spectrum ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous ◽  
Absorption Tail

AbstractThe role that disorder plays in shaping the form of the optical absorption spectrum of hydrogenated amorphous silicon is investigated. Disorder leads to a redistribution of states, which both reduces the ‘Tauc’ gap and broadens the absorption tail. The observed relationship between the ‘Tauc’ gap and the breadth of the absorption tail is thus explained.

Sub-Bandgap Optical Absorption in Amorphous Silicon using Photo-Pyroelectric Spectroscopy

1991 ◽  
Vol 219 ◽  
Author(s):  
J. Fan ◽  
J. Kakalios
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Wavelength Dependence ◽  
Sample Thickness ◽  
Pyroelectric Effect ◽  
Radiative Quantum Efficiency ◽  
Set Up ◽  
Hydrogenated Amorphous

ABSTRACTMeasurements of the optical absorption spectrum of doped and undoped hydrogenated amorphous silicon (a-Si:H) for photon energies ranging from 0.8 to 2.5 eV are obtained using photo-pyroelectric spectroscopy (PPES). This technique, based upon the pyroelectric effect, has a simpler experimental set-up than photo-thermal deflection spectroscopy, and presently has a sensitivity of ad > 10-3, where d is the sample thickness. In addition, using PPES we have measured the non-radiative quantum efficiency in a-Si:H, and find that it has a strong wavelength dependence for sub-bandgap illumination.

Optical absorption, disorder, and hydrogen in amorphous silicon

1996 ◽  
Vol 74 (S1) ◽  
pp. 256-259 ◽  
Author(s):  
Stephen K. O'Leary ◽  
Lakhbeer S. Sidhu ◽  
Stefan Zukotynski ◽  
John M. Perz
Keyword(s):  
Absorption Spectrum ◽  
Standard Deviation ◽  
Optical Absorption ◽  
Amorphous Silicon ◽  
Density Of States ◽  
Hydrogen Concentration ◽  
Optical Absorption Spectrum ◽  
Energy Gap ◽  
Local Form ◽  
Absorption Data

We study how bonded hydrogen influences the optical absorption spectrum of amorphous silicon. We use a model for optical absorption in which the local form of the joint density of states is averaged over a Gaussian distribution of energy-gap fluctuations, this distribution being characterized by a mean energy gap and a standard deviation about this mean. We then fit this model to optical absorption data, and study how the modeling parameters vary with the bonded hydrogen concentration. We find that for the group of samples that we have considered, for bonded-hydrogen concentrations less than 10 at.%, we can adequately fit the data with a constant mean energy gap and a variable standard deviation that decreases with increasing bonded-hydrogen concentration. This suggests that bonded hydrogen plays a significant role in decreasing the amount of disorder in amorphous silicon.

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