task3pn junction of semiconductor npn.pptx

pn junction

1. Semiconductor Junction of n and p type materials and behavior of diode in forward and reverse biased Presented By: Maaz Bin Fazal Course: Applied Physics Course Instrcutor : Dr.Abid Munir Summer Semester 2024

2. Comparison of Semiconductor Junctions: Forward Bias vs. Reverse Bias Aspect Forward Bias Reverse Bias Definition Positive terminal of the power source is connected to the p-type material (anode) and the negative terminal to the n-type material (cathode). Positive terminal of the power source is connected to the n-type material (cathode) and the negative terminal to the p-type material (anode). Depletion Region Narrowed because the applied voltage reduces the potential barrier. Widened because the applied voltage increases the potential barrier. Carrier Movement Majority carriers (holes in p-type and electrons in n-type) move towards the junction, leading to recombination. Majority carriers are pulled away from the junction, widening the depletion region. Minority carriers contribute to a small leakage current. I-V Characteristic Exponential increase in current with increasing voltage beyond the threshold. Very small leakage current; characteristic curve shows a flat region with a sharp increase in current at breakdown. Breakdown Not applicable under normal forward bias conditions. Breakdown occurs if the reverse voltage exceeds a critical value, leading to a sharp increase in current (e.g., avalanche or Zener breakdown).