摘要
The directional, averaged, and density-of-states effective masses of holes have been calculated for strained Si/(111)Si1-xGex. The results for the directional effective mass show that the effect of strain makes the constant energy surface of "heavy" holes more obvious warping than that in relaxed Si. The [111] and [110] directional effective masses of "heavy" holes decrease significantly under strain. It is found that the averaged effective mass of "heavy" holes decreases with increasing Ge fraction, while that of "light" holes increases. The traditional concepts of heavy and light holes become insignificant when Ge fraction is close to 0.4. The strain effect monotonically reduces the density-of-states effective mass at 218, 300 and 393 K, respectively.
The directional, averaged, and density-of-states effective masses of holes have been calculated for strained Si/（111）Si1-xGex. The results for the directional effective mass show that the effect of strain makes the constant energy surface of “heavy” holes more obvious warping than that in relaxed Si. The [111] and [110] directional effective masses of “heavy” holes decrease significantly under strain. It is found that the averaged effective mass of “heavy” holes decreases with increasing Ge fraction, while that of “light” holes increases. The traditional concepts of heavy and light holes become insignificant when Ge fraction is close to 0.4. The strain effect monotonically reduces the density-of-states effective mass at 218, 300 and 393 K, respectively.
基金
supported by the National Ministries and Commissions (Grant Nos. 51308040203 and 6139801)
the Fundamental Research Funds for the Central Universities (Grant Nos. 72105499 and 72104089)
the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2010JQ8008)
