\documentclass[border=3pt]{standalone}
% Circuits
\usepackage[european,s traightvoltages, RPvoltages, americanresistor, americaninductors]{circuitikz}
\tikzset{every picture/.style={line width=0.2mm}}
% Notation
\usepackage{amsmath}
% Bipoles Specifications
\ctikzset{bipoles/thickness=1.2, label distance=1mm, voltage shift = 1}
\begin{document}
\begin{circuitikz}
%%Grid
%\def\length{4}
%\draw[thin, dotted] (-\length,-\length) grid (\length,\length);
%\foreach \i in {1,...,\length}
%{
% \node at (\i,-2ex) {\i};
% \node at (-\i,-2ex) {-\i};
%}
%\foreach \i in {1,...,\length}
%{
% \node at (-2ex,\i) {\i};
% \node at (-2ex,-\i) {-\i};
%}
%\node at (-2ex,-2ex) {0};
% PN Contact
\draw[fill=black!15, draw=black, line width = 0.2mm] (-3.5,0) rectangle (-2.5,1);
\draw[line width = 0.2mm] (-2.5,0) rectangle (-1.5,1);
\node at (-3,0.5) {p};
\node at (-2,0.5) {n};
\draw (-3.5,0.5) -- (-4,0.5) node[left] {A};
\draw (-1.5,0.5) -- (-1,0.5) node[right] {K};
\draw [-{Triangle[round]}] (-3,-0.5) -- (-2,-0.5) node[pos=0.5,below] {$I$};
% Diode
\draw (1,0.5) node[left] {A} to[full diode] (3,0.5) node[right] {K};