Cross-sectional HRTEM images of sandwich structure with (a) evaporated Ge thin film (amorphous film is ) and (b) Ge NCs (the NC size is ) embedded in .
The hystereses for samples A and B with measured frequency at , respectively. (Sweep gate voltage back and forth between and .) There exists a dramatically larger curve shift to the positive voltage for sample A than for sample B at the measurement. The hysteresis windows measured at the various frequencies for the two samples are all shown in the inset and maintain the same value of for our applied frequencies in sample A (B).
The and from for the forward sweep with different frequencies for (a) sample A and (b) sample B. The inset shows the comparative relation of and curves at for samples A and B.
Schematic diagram of equivalent circuit model for a NC MOS structure, where capacitance, capacitance, capacitance, capacitance, conductance, and resistance.
The trap conductance vs gate voltage for samples A and B. It shows the narrower distributed peak and reduction of magnitude after PMA treatment.
A model with energy diagram in weak accumulation regime. It represents the slow traps, interface traps, and fast traps induced by NC formation. The inset also shows the energy diagram in depletion regime. The stored charges are attracted by the negative gate bias and kept the same from the weak accumulation to depletion regimes.
The values of vs at the five different frequencies from by steps of for sample A with five respective solid symbols. The solid lines which connect the solid symbols under the same respective gate voltage demonstrate a linear relationship.
The resulted values of are calculated with Eq. (2) for both samples. The bias range is limited from the weak accumulation to depletion regimes. It is found that the variation of resulting vs gate bias almost has the same trend and almost indicates independence from frequency in both samples. The inset shows averaged values of for the five different frequencies and corresponding stand and deviations in both samples.
The are obtained experimentally and calculated theoretically for samples A and B with individual applied frequency from formula in Eq. (1). The inset shows the extracted from Eq. (3) of samples A and B. It demonstrates the similar variations and magnitudes of for both samples.
The vs gate voltage of samples A and B. It becomes smaller by one order of magnitude at the same gate bias after PMA treatment.
The variations in both samples vs gate bias in five different frequencies from that evaluated with . It represents similar curves with curves, especially in depletion regime .
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