The photodiode is a semiconductor device responsive to high-energy particles and photons. It operates by absorption of photons or charged particles and generates a flow of current in an external circuit, proportional to the power. It has an effective working principle but it has many other advantages. But you have to know its disadvantages too.
Advantages of photodiode
The photodiode has the following benefits:
- It is highly sensitive to light. It shows a quick response when exposed to light.
- It has a better frequency response and spectral response compared to LDR.
- It is a linear circuit element. The photocurrent of the photodiode is extremely linear to the light level.
- It can be manufactured from a variety of materials including, but not limited to, silicon, germanium, and indium gallium arsenide.
- It can operate at high frequencies.
- It has a lower noise level.
- It is the fastest photodetector. The speed of the operation is extremely fast.
- It has a low resistance but it can be used as a variable resistance. The intensity of the reverse light current varies with the intensity of the incident light energy for the fixed reverse bias voltage. Thus, the ratio of voltage to the current varies. So, there will be a variation in the resistance of the photodiode.
- It has a low dark current.
- It has a long lifetime. It can be used for years without any maintenance.
- It has a compact size.
- It requires no high voltage.
- It is durable, reliable, and can withstand mechanical stress.
- It is having a high quality/price performance.
- It finds use in a wide range of applications because it can be made with a wide range of performance characteristics. Each application places different demands on its performance. Available in a wide range of packages including epoxy coated, transfer molded, cast, and hermetic packages as well as in chip form.
- It is utilized in such diverse applications as spectroscopy, photography, analytical instrumentation, safety equipment, optical position sensors, beam alignment, surface characterization, laser range finders, optical communications, and medical imaging instruments.
- It is usable with almost any visible or near-infrared light source such as LEDs; neon, fluorescent, incandescent bulbs; lasers; flame sources; sunlight; etc.
- It can be designed and tested to meet the requirements of your application.
Disadvantages of photodiode
The photodiode has the following drawbacks:
- It has poor temperature stability. When the temperature increases, the dark current level also increases rapidly. Ambient temperature variations greatly affect its sensitivity and dark current.
- It has a small active area.
- There is a necessity for amplification at low irradiances.
- It needs offset voltage.
- Change in current is very small, hence may not be sufficient to drive the circuit.
- Should not exceed the working temperature limit specified by the manufacturers.