which of the following statements are true about semiconductor ?
(a)silicon doped with electron rich impurity is a p-type semiconductor
(b)Silicon doped with an electrons rich impurity is an n-type semiconductor
(c)Delocalised electrons increase the conductivity of doped silicon
(d)An electron vacancy increase the conductivity of n- type semiconductor

Options

A. silicon doped with electron rich impurity is a p-type semiconductor
B. Silicon doped with an electrons rich impuriy is an n-type semipucoter
C. Delocalised electrons increase the conductivity of doped silicon
D. An electron vacancy incease the conductivity of n- type semiconductor

Explanation

To determine which statements about semiconductors are true, let's analyze each statement step by step.

### Step 1: Analyze Statement (a)
**Statement (a): Silicon doped with electron-rich impurity is a p-type semiconductor.**

- **Explanation:** P-type semiconductors are formed when silicon is doped with electron-poor impurities (such as boron), which create holes (positive charge carriers). When silicon is doped with electron-rich impurities (like phosphorus), it results in an n-type semiconductor, which has excess electrons.

- **Conclusion:** This statement is **false**.

### Step 2: Analyze Statement (b)
**Statement (b): Silicon doped with an electron-rich impurity is an n-type semiconductor.**

- **Explanation:** As mentioned earlier, when silicon is doped with electron-rich impurities, it leads to the formation of an n-type semiconductor. The extra electrons provided by the dopant increase the conductivity of the material.

- **Conclusion:** This statement is **true**.

### Step 3: Analyze Statement (c)
**Statement (c): Delocalized electrons increase the conductivity of doped silicon.**

- **Explanation:** In n-type semiconductors, the presence of delocalized electrons (free electrons) contributes significantly to electrical conductivity. The more delocalized electrons available, the higher the conductivity.

- **Conclusion:** This statement is **true**.

### Step 4: Analyze Statement (d)
**Statement (d): An electron vacancy increases the conductivity of n-type semiconductor.**

- **Explanation:** In n-type semiconductors, the conductivity is primarily due to the presence of free electrons. Electron vacancies (or holes) do not contribute to the conductivity in n-type materials; they are more relevant in p-type semiconductors where they represent the absence of electrons.

- **Conclusion:** This statement is **false**.

### Final Summary of Statements:
- (a) False
- (b) True
- (c) True
- (d) False

### True Statements:
The true statements about semiconductors are **(b)** and **(c)**.

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