科研之友
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摘要
Temperature-dependent conductance-frequency, capacitance-frequency and current-voltage measurements have been carried out on hydrogenated nanocrystalline silicon (nc-Si:H) films grown by plasma-enhanced chemical vapor deposition. The nanocrystalline size of the films, obtained from Raman scattering and X-ray diffraction measurements, is found to be consistent with the observed Coulomb-blockade effect at temperature below 150 K, which demonstrates the good order of the nanostructure thin films. An improved series resistance equivalent circuit model has been proposed to extract valuable electrical information of the nanocrystalline Si samples. The frequency dependence of AC conductance at low temperature is similar to that of the amorphous materials, indicating that the hopping conduction plays an important role in nc-Si:H at low temperature. The temperature dependence of AC conductance reveals an overlapping large polaron tunneling mechanism in nc-Si:H. The temperature-dependent capacitance is found to be determined by the competition of carrier charging/discharging processes between the energy levels of the natural quantum dots and the localized states of the amorphous interface regions, and therefore shows frequency dependence.
- 出版日期2003-8
- 单位上海交通大学
