When arsenic is added as an impurity to silicon, the resulting material is

Options

A. n-type semiconductor
B. p-type semiconductor
C. n-type conductor
D. insulator

Answer

To solve the question, we need to understand the effects of adding impurities to silicon, which is a semiconductor. Here's a step-by-step breakdown of the solution:

### Step 1: Identify the type of impurity
Arsenic (As) is a pentavalent impurity. This means that it has five valence electrons.

**Hint:** Remember that pentavalent impurities have five valence electrons, while trivalent impurities have three.

### Step 2: Understand the semiconductor doping process
When a pure semiconductor like silicon (Si), which has four valence electrons, is doped with a pentavalent impurity, the extra valence electrons from the impurity will contribute to electrical conduction.

**Hint:** Doping refers to the intentional introduction of impurities into a semiconductor to change its electrical properties.

### Step 3: Determine the type of semiconductor formed
When a pentavalent impurity like arsenic is added to silicon, it donates extra electrons to the conduction band of silicon. This results in an increase in the number of free electrons available for conduction, which characterizes n-type semiconductors.

**Hint:** N-type semiconductors are characterized by an abundance of free electrons, while p-type semiconductors have holes (absence of electrons).

### Step 4: Conclusion
Since arsenic is a pentavalent impurity and it is added to silicon, the resulting material will be an n-type semiconductor.

**Final Answer:** The resulting material is an n-type semiconductor.