Question

Plot a graph showing the variation of current with voltage for the material GaAs. On the graph, mark the region where: \textbf{(a) resistance is negative, and

Hint:

For semiconductors like GaAs, identify negative resistance regions by looking for sections of the $I$-$V$ curve with a negative slope.

Answer 1

Gallium arsenide (GaAs) exhibits negative resistance in certain regions of its current-voltage ($I$-$V$) characteristic curve. The graph typically shows a linear region (Ohm’s law), followed by a region of negative slope (negative resistance), and then a saturation region.
The regions can be identified as follows:
\begin{itemize} \item (a) The region where resistance is negative corresponds to the portion of the $I$-$V$ curve with a negative slope (decreasing current with increasing voltage).
\item (b) The region where Ohm’s law is obeyed corresponds to the initial linear part of the $I$-$V$ curve. \end{itemize}
A qualitative sketch of the $I$-$V$ graph is shown below:
\includegraphics[width=0.4\linewidth]{11image.png} The graph marks the linear region for Ohm’s law and the negative resistance region.