The breakdown in a reverse biased p-n junction diode is more likely to occur due to

Options

A. large velocity of the minority charge carriers if the doping concentration is small
B. large velocity of the minority charge carriers if the doping concentration is large
C. strong electric field in a depletion region if the doping concentration is small
D. none of these

Explanation

To solve the question regarding the breakdown in a reverse-biased p-n junction diode, we need to analyze the conditions under which breakdown occurs. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understanding Reverse Bias
In a reverse-biased p-n junction diode, the negative terminal of the battery is connected to the p-type material, and the positive terminal is connected to the n-type material. This configuration widens the depletion region and prevents current flow under normal conditions.

**Hint:** Remember that in reverse bias, the majority carriers are pulled away from the junction, increasing the depletion region.

### Step 2: Role of Minority Charge Carriers
In reverse bias, the current is primarily due to minority charge carriers. In a p-type material, electrons are the minority carriers, while in an n-type material, holes are the minority carriers. Under reverse bias, only these minority carriers contribute to the current.

**Hint:** Identify which carriers are minority carriers in p-type and n-type materials.

### Step 3: Effect of Increasing Reverse Voltage
As the reverse voltage increases, the electric field across the depletion region becomes stronger. This increased electric field can accelerate the minority carriers, leading to more collisions as they cross the junction.

**Hint:** Consider how increasing voltage affects the movement of charge carriers across the junction.

### Step 4: Breakdown Mechanism
When the reverse voltage reaches a critical level, the collisions between accelerated minority carriers can lead to a chain reaction, where more carriers are generated, resulting in a significant increase in current. This phenomenon is known as avalanche breakdown.

**Hint:** Think about how collisions can lead to the generation of more charge carriers.

### Step 5: Doping Concentration
The likelihood of breakdown is influenced by the doping concentration. Low doping levels result in fewer majority carriers, allowing minority carriers to cross the junction more easily. In contrast, high doping levels increase the concentration of majority carriers, which can impede the flow of minority carriers and reduce the likelihood of breakdown.

**Hint:** Relate the doping concentration to the behavior of majority and minority carriers.

### Conclusion
The breakdown in a reverse-biased p-n junction diode is more likely to occur due to low doping levels, which allows for a larger velocity of minority charge carriers and facilitates their crossing over the junction, leading to collisions and eventual breakdown.

**Final Answer:** The breakdown in a reverse-biased p-n junction diode is more likely to occur due to low doping levels, which allows for a larger velocity of minority charge carriers.