| Working Principle | Zener Breakdown | Avalanche Breakdown | Quantum Tunneling | Photoelectric Effect | Electroluminescence | Metal-Semiconductor Junction |
| Biasing Mode | Reverse Bias | Reverse Bias | Forward Bias | Reverse Bias | Forward Bias | Forward Bias |
| Doping Level | Heavily Doped | Lightly Doped | Extremely Heavily Doped | Moderately Doped | Moderately Doped | N-Type Semiconductor + Metal |
| Depletion Region | Very Thin | Wide | Extremely Thin | Moderate | Moderate | Very Thin |
| Operating Voltage | Low (< 5–6 V) | High (> 6 V) | Very Low | Reverse Voltage | 1.5–3.5 V | 0.2–0.4 V |
| Breakdown Mechanism | Zener Effect | Impact Ionization | Tunneling Effect | Light Generated Current | Light Emission | Majority Carrier Conduction |
| Negative Resistance Region | No | No | Yes | No | No | No |
| Switching Speed | Fast | Fast | Extremely Fast | Fast | Fast | Very Fast |
| Power Dissipation | Moderate | High | Low | Low | Low | Low |
| Temperature Coefficient | Negative | Positive | Negative | Depends on Material | Depends on Material | Small |
| Junction Type | PN Junction | PN Junction | PN Junction | PN Junction | PN Junction | Metal-Semiconductor |
| Current Carrier | Majority + Minority | Majority + Minority | Majority Carrier | Light Generated Carriers | Electron-Hole Recombination | Majority Carrier |
| Light Sensitive | No | No | No | Yes | No | No |
| Light Emitting | No | No | No | No | Yes | No |
| Reverse Recovery Time | Moderate | Moderate | Very Low | Low | Low | Extremely Low |
| Noise Level | Low | High | High | Low | Low | Low |
| Efficiency | High Regulation | High Protection | High Speed | High Sensitivity | High Efficiency | High Efficiency |
| Main Application | Voltage Regulation | Surge Protection | Microwave Oscillator | Light Detection | Display/Lighting | High-Speed Rectifier |