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 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.

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