\begin{axis}[ xlabel=$n$
            , ylabel=$\nicefrac{g_{\mathrm{m}}}{I_{\mathrm{D}}}|_{\mathrm{max}}$ in \si{\per\volt}
            , xmin=1
            , xmax=1.6
            , ymin=15
            , ymax=50
            , grid=both
            , width=9cm
            ]

  \tikzstyle{plotprop} = [ mark=none
                         , domain=1:1.6
                         , samples=20
                         , smooth
                         , thick
                         ]
  \tikzstyle{annonode} = [ fill=white
                         , inner sep=1pt
                         ]

  \def \echarge {1.602e-19}
  \def \kboltz {1.38064852e-23}
  \def \tkelvin {273.15}

  \addplot[plotprop] {\echarge/(\kboltz*\x*300)}; 
  \node[ annonode
       , anchor=north west
       , rotate=-20
       ] at (axis cs:1.1,34.7) {\SI{300}{\kelvin}};

  \addplot[plotprop] {\echarge/(\kboltz*\x*(-40+\tkelvin))}; 
  \node[ annonode
       , anchor =north west
       , rotate=-20
       ] at (axis cs:1.1,26.3) {\SI{-40}{\celsius}};

  \addplot[plotprop] {\echarge/(\kboltz*\x*(0+\tkelvin))};
  \node[ annonode
       , anchor =north west
       , rotate=-18
       ] at (axis cs:1.1,29.3) {\SI{0}{\celsius}};

  \addplot[plotprop] {\echarge/(\kboltz*\x*(85+\tkelvin))}; 
  \node[ annonode
       , anchor =north west
       , rotate=-22
       ] at (axis cs:1.1,38.25) {\SI{85}{\celsius}};

  \addplot[plotprop] {\echarge/(\kboltz*\x*(125+\tkelvin))}; 
  \node[ annonode
       , anchor =north west
       , rotate=-27
       ] at (axis cs:1.1,44.8) {\SI{125}{\celsius}};
\end{axis}