Statement I: When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N – type semiconductor such that P – type has excess holes and N – type has excess electrons.

Statement II: When such P – type and N – type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ammeter.

 

In the light of above statements, choose the most appropriate answer from the options given below 

Statement I: Is correct and statement II is correct
i) When silicon has four valency electrons and boron has three valency electrons. So these three valency electrons bond with four electrons of silicon atom taken. This creates a hole (or) vacancy. As a result P –type semi – conductor is formed.
ii) Where as arsenic has a pentavalent, so doping with silicon, their remains one free electron. Thus N– type is formed.
iii) p – side has excess of holes and n – type excess of electrons in the outer shells of electrically neutral atoms. This allows electric current to pass through the junction only in one direction.