Germanium has been doped with impurity as shown in I, II, III and IV and based as it statements

A. n-type semiconductor is formed in I and III
B. p-type semiconductor is formed in II and IV
C. P-type semiconductor is formed in II and IV
D. p-type semiconductor is formed in I and III Select the correct statement(s).

Options

A. A,B
B. C,D
C. A,D
D. A,B,C

Explanation

I and III have been doped with pentavalent impurity (P and As). There in one surplus electron that results in the formation of n-type semiconductor and thus conducting. In II and IV, doping has been done using trivalent B and Al.