光电导归一化法测量-Si:H隙态密度
MEASUREMENT OF THE DENSITY OF THE GAP STATES IN a-Si:H BY THE NORMALIZATION OF PHOTOCONDUCTIVITY
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摘要: 本文用光电导归一化法得出 -Si:H膜在低吸收区的光吸收系数谱;用电子从价带的指数尾态和导带边以下1.0 eV处,由悬挂键形成的局域态到导带扩展态的跃迁,解释了实验结果;并从而得出费米能级EF以下的隙态密度,通过对复合动力学的研究,还得到费米能级以上(EFn-EF)的局域态密度的平均值,从而得出费米能级以上部份的态密度。结果表明导带尾比价带尾窄。
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Abstract: The spectra of the optical absorption conficient in the low absorption region are obtained by using a normalization procedure for the photoconductivity spectra. The results are explained in terms of optieal transitions of electrons from loealized states in exponential valence-band tail and in danglihg bond states. 1.0 eV below the conduction-band edge to extended states above the conduction-band edge. Then the density of the gap states below the Fermi energy EF is abtained. From the investigation of recombination kinetics, the average density of the gap states in the range of (EFn-EF) is obtained. Then the density of the gap states above the Fermi energy EF is obtained. It indicates that the width of the conduction-band tail is narrower than that of valence-band tail. -
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