When a diode is forward biased, the recombination of the free electrons and holes may produce?
Right Answer is:
All of the above
Recombination of electron-hole pair Produce
- Heat energy
- Light energy
- Radiation energy
GENERATION AND RECOMBINATION
In semiconductors, a single event of covalent bond breaking leads to the generation of two charge carriers, an electron in the conduction band and a hole in the valence band. The process may be represented as
Covalent Bond + Thermal Energy ⇒ (Electron + Hole)Pairs
As electron and hole are produced simultaneously, the process is called electron-hole pair generation. In the process of generation, a covalent bond is broken and a bound electron is transformed into a free electron. Thermal energy is one of the agents which causes pair generation.
It is likely that the electron in the conduction band may lose its energy due to collision with other particles in the lattice and fall into the valence band. When a free electron falls into a valence band, it merges with a hole. This process is called recombination. When a recombination event occurs, the free electron enters a ruptured covalent bond and re-bridges it.
Therefore, recombination means that a free electron transforms into a valence electron and that a ruptured covalent bond is re-bridged. In the process, an electron-hole pair disappears and energy is released. The released energy is mainly in the form of thermal energy.
Electron + Hole ⇒ Covalent Bond + Energy
At a steady temperature, a dynamic equilibrium exists which balances the two processes of electron-hole pair generation and electron-hole recombination.