TY - GEN

T1 - INTERBAND OPTICAL ABSORPTION IN AMORPHOUS SEMICONDUCTORS.

AU - Cohen, Morrel H.

AU - Soukoulis, Costas M.

AU - Economou, E. N.

PY - 1984/12/1

Y1 - 1984/12/1

N2 - A simple, analytic derivation is presented of the exponential tails universally observed in the optical absorption of three-dimensional disordered systems based on recent analysis of exponential band tails. These tails contain states localized inside relatively large regions within which the local average of the potential falls below its overall average. The physical extent of a tail state is governed by the fluctuation size and not the localization length. Strong anticorrelation in the fluctuations of the valence and conduction band edges implies that the Urbach tail arises from valence tail to conduction tail transitions. Otherwise, the urbach tail arises from a superposition of valence tail to conduction extended and valence extended to conduction tail state transitions. The wider band tail then dominates the Urbach tail, as inthe case, e. g. , for a-Si:H, where the valence band tail dominates.

AB - A simple, analytic derivation is presented of the exponential tails universally observed in the optical absorption of three-dimensional disordered systems based on recent analysis of exponential band tails. These tails contain states localized inside relatively large regions within which the local average of the potential falls below its overall average. The physical extent of a tail state is governed by the fluctuation size and not the localization length. Strong anticorrelation in the fluctuations of the valence and conduction band edges implies that the Urbach tail arises from valence tail to conduction tail transitions. Otherwise, the urbach tail arises from a superposition of valence tail to conduction extended and valence extended to conduction tail state transitions. The wider band tail then dominates the Urbach tail, as inthe case, e. g. , for a-Si:H, where the valence band tail dominates.

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M3 - Conference contribution

AN - SCOPUS:0021614964

SN - 0883183196

T3 - AIP Conference Proceedings

SP - 371

EP - 378

BT - AIP Conference Proceedings

A2 - Taylor, P.C.

A2 - Bishop, S.G.

PB - AIP

ER -