We have numerically studied the band structure and the spin polarization effect in a periodic one-dimensional array of quantum point contacts (QPCs) formed in a two-dimensional electron gas in a plane-layered semiconductor system. In this study we used a self-consistent model developed within the framework of the Kohn-Sham local spin-density formalism. We have found that the band structure contains a mixture of flat and dispersed bands, and the role of transverse modes in the formation of such a band structure has been clearly demonstrated. We have also shown that spin polarization occurs mainly in the regions occupied by the QPCs and that it is qualitatively similar to the spin polarization in a single QPC.

We have bias-stressed hydrogen-passivated polycrystalline silicon thin-film transistors by varying the bias condition and have measured the change in the field-effect conductance activation energy as a result of the bias stress. For stress by a high gate bias voltage, a slight broadening occurs in the activation energy curve, while stress by a low gate bias voltage gives rise to a shoulder. Numerical calculation shows that the change in activation energy is due to defect generation in the poly-Si layer and for stress by low gate voltage, defects are localized near the drain region. The energy distribution of defects cannot be obtained accurately, but its position is higher than 0.2 eV above midgap.