TY - JOUR
T1 - Urbach tail, disorder, and localized modes in ternary semiconductors
AU - Bonalde, Ismardo
AU - Medina, Ernesto
AU - Rodríguez, Miguel
AU - Wasim, S. M.
AU - Marín, G.
AU - Rincón, C.
AU - Rincón, A.
AU - Torres, C.
PY - 2004/5
Y1 - 2004/5
N2 - We analyze the role of localized modes, produced by structural disorder, in the formation of the optical-absorption edge in semiconductors. Such modes give rise to an additional energy h δvd, above the average of the optical modes in the ordered sample. In the present study, this interpretation is confirmed experimentally from a study of infrared absorption spectra of several samples of the semiconductor CuGaTe2. The high value of h vp found in these samples, higher than the average of the 14 Raman modes of the ordered sample, is in good agreement with the average of all the optical and localized modes. Previous models involving disorder are discussed and derived from the thermal/disorder broadening of a harmonic oscillator with average frequency associated with the measured phonon modes. Our quantitative interpretation in terms of phonon frequency shift can be extended to a more general class of crystalline/amorphous semiconducting materials.
AB - We analyze the role of localized modes, produced by structural disorder, in the formation of the optical-absorption edge in semiconductors. Such modes give rise to an additional energy h δvd, above the average of the optical modes in the ordered sample. In the present study, this interpretation is confirmed experimentally from a study of infrared absorption spectra of several samples of the semiconductor CuGaTe2. The high value of h vp found in these samples, higher than the average of the 14 Raman modes of the ordered sample, is in good agreement with the average of all the optical and localized modes. Previous models involving disorder are discussed and derived from the thermal/disorder broadening of a harmonic oscillator with average frequency associated with the measured phonon modes. Our quantitative interpretation in terms of phonon frequency shift can be extended to a more general class of crystalline/amorphous semiconducting materials.
UR - http://www.scopus.com/inward/record.url?scp=37649029069&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.69.195201
DO - 10.1103/PhysRevB.69.195201
M3 - Artículo
AN - SCOPUS:37649029069
SN - 0163-1829
VL - 69
SP - 195201-1-195201-5
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 19
M1 - 195201
ER -