1 Erratum to: Appl. Phys. A (2016) 122:226 DOI 10.1007/s00339-016-9740-4

The original version of this article unfortunately contained a mistake. The presentation of Eq. 7 was incorrect. The correct version is given below.

$$ S = \frac{{K_{\text{B}} }}{e}\left( {A + \ln \left( {\frac{{2\left( {2\pi m^{*} K_{\text{B}} /h^{2} } \right)^{{\frac{3}{2}}} }}{{n_{\text{s}} }}} \right)} \right) $$
(7)