A band model for synthetic dopa-melanin.

Physiological chemistry and physics Pub Date : 1982-01-01
T Strzelecka
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引用次数: 0

Abstract

To determine a band model for synthetic melanin obtained by autooxidation of L-dopa (3,4-dihydroxyphenyl-L-alanine), dependence of dark current on temperature in the range 298-333 degrees K was measured as well as dependence of optical absorption coefficient on wave-length in the range 250-800 nm. It was found that up to 311 degrees K thermal activation energy equals 0.1 eV and above 313 degrees K it equals 0.78 eV. The first value is connected with the band of localized states at the Fermi level. Optical gap, determined from optical absorption measurements is equal to 1.40 eV. The estimated value of sigma o, assuming the value of thermal coefficient of activation-energy to be gamma = 5 X 10(-4) eV/degrees K, is 2 X 10(-6) omega -1 cm-1 for 0.1 eV and 5 X 10(2) omega -1 cm-1 for 0.78 eV. Density of states in the valence band is N(EV) = 8 X 10(21)/cm3 X eV, and in the band of localized states at the Fermi level N(EF) = 3 X 10(13)/cm3 X eV.

合成多巴-黑色素的波段模型。
为了确定L-dopa(3,4-二羟基苯基-l -丙氨酸)自氧化合成黑色素的波段模型,测量了暗电流对298-333°K范围内温度的依赖性以及250-800 nm范围内光吸收系数对波长的依赖性。结果表明,在311℃以下的热活化能为0.1 eV, 313℃以上的热活化能为0.78 eV。第一个值与费米能级的局域态带有关。由光吸收测量确定的光隙等于1.40 eV。假设活化能热系数的值为gamma = 5 X 10(-4) eV/度K,则sigma o的估计值为2 X 10(-6) omega -1 cm-1 (0.1 eV)和5 X 10(2) omega -1 cm-1 (0.78 eV)。价带态密度N(EV) = 8 X 10(21)/cm3 X EV,费米能级局域态密度N(EF) = 3 X 10(13)/cm3 X EV。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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