Energy relaxation of two-dimensional carriers in strained Ge/Si0.4Ge0.6 and Si/Si0.7Ge0.3 quantum wells: Evidence for two-dimensional acoustic phonons

초록

We performed heating measurements on holes in a strained Ge/Si0.4Ge0.6 quantum well and electrons in a strained Si/Si0.7Ge0.3 quantum well in the temperature range 0.3-5.5 K. While a power law dependence of carrier temperature on current, T-e - I-a, was observed for both samples, the measured values for the current exponent are different: a = 0.50 +/- 0.02 for the Ge sample and 0.40 +/- 0.02 for the Si sample. We attribute this exponent difference to the difference in their phonon dimensionality.

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