Question

A semiconductor $X$ is made by doping a Germanium crystal with Arsenic $(Z=33)$. A semiconductor Y is made by doping Germanium with Indium $(Z=49)$. The two are joined end to end and connected to a battery as shown. Which of the following statements is correct?

• A. $X$ is p-type, $Y$ is n-type and the junction is forward biased
• B. $X$ is n-type, $Y$ is p-type and the junction is forward biased
• C. $X$ is p-type, $Y$ is n-type and the junction is reverse biased
• D. $X$ is n-type, $Y$ is p-type and the junction is reverse biased

Answer 1

The correct option is D $X$ is n-type, $Y$ is p-type and the junction is reverse biased


As given, $X$ is dopped by $Ar(Z=33)$
$Y$ is dopped by $In(Z=49)$
$Ar$ having pentavalent impurity, hence it works as a n-type semiconductor.
And as $In$ having trivalent impurity, hence it works as a p-type semiconductor.


As positive terminal of battery is connected to X which is pentavalent and negative terminal is connected to Y which is trivalent and from the above dig. we can see that system works as a reverse bias.
Hence, option D is correct