Radiation Diode Detector Doping question.

In summary, the conversation discusses the fundamentals of semiconductors and the formation of a diode with a depletion layer when n-type and p-type substrates are combined. The question arises about radiation detectors and the use of small amounts of impurities to dope the diodes, with the confusion surrounding the opposite doping of the n-type substrate. The paper referenced explains the instantaneous dose rate dependence of radiation diode detectors, but the original question remains unanswered. The most convenient way to make a diode is by doping one side of a substrate with different polarity, but the minority carrier concentration and the need for fusing the junction for contact can complicate the process.
  • #1
venomxx
39
0
I'm reading up on semiconductors and there seems to be a few fundamentals I cannot find answers for if anyone can help?

I understand that n-type substrate is doped with a donor and p-type substrate is doped with an acceptor creating excess electrons and holes. When you put the p-type and n-type together you get a diode with a depletion layer.

My problem comes with radiation detectors. In the paper below it states that a p-type diode (not substrate) is when you dope small amounts of donor impurities into a p-type substrate. Also a n-type diode (not substrate) is when you dope small amounts of acceptor impurities into a p-type substrate. Why dope the n-type with the opposite (p-type) donor? Is this not just undoing the original doping?

So if this is right, you dope the n-portion of a p-n junction with the opposite doping (acceptors) to form an N-type diode?

Paper: "Modeling the instantaneous dose rate dependence of radiation diode detectors" Jie Shie and William E. Simon Med. Phys 30(9), Sept 2003

Please clarify! Any help is appreciated!
 
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  • #3
Bump! Can anyone provide any help/resources?
 
  • #4
The most convenient way to make a diode is taking a substrate and doping one side with different polarity.
 
  • #5
Kholdstare said:
The most convenient way to make a diode is taking a substrate and doping one side with different polarity.

Thanks for the reply, to clarify:

Do you mean taking an n-type substrate and doping acceptors on one side of the substrate with a high enough concentraton to change the majority carriers from electrons to holes?
Thus you would have a bigger minority carrier concentration on the p-side then just joining n-type and p-type substrates together to form the junction?
 
  • #6
Minority carrier concentration depends on built-in potential, doping etc.
To make a diode by joining n and p type you have to fuse the junction to make a contact. The high temperature damages the crystal.
 

1. What is a radiation diode detector?

A radiation diode detector is a device that is used to detect and measure ionizing radiation, such as gamma rays or X-rays. It is made up of a semiconductor material, typically silicon, which is doped with impurities to create a p-n junction. When radiation passes through the detector, it produces electrical signals that can be measured and used to determine the type and intensity of the radiation.

2. How does a radiation diode detector work?

A radiation diode detector works by using the principles of the p-n junction. When ionizing radiation passes through the detector, it creates electron-hole pairs in the semiconductor material. These charges are then separated by the electric field of the p-n junction, creating a measurable current. The strength of this current is directly proportional to the intensity of the radiation, allowing for accurate measurements.

3. What is doping and how does it affect the performance of a radiation diode detector?

Doping is the process of adding impurities, such as boron or phosphorus, to a semiconductor material in order to change its electrical properties. In a radiation diode detector, doping is used to create the p-n junction and control the flow of electrical charges. The type and concentration of dopants used can affect the sensitivity and efficiency of the detector, so careful selection is important for optimal performance.

4. What types of radiation can a radiation diode detector detect?

A radiation diode detector can detect various types of ionizing radiation, including gamma rays, X-rays, and beta particles. The sensitivity of the detector may vary depending on the type of radiation, so it is important to select the appropriate detector for the specific application.

5. How is a radiation diode detector used in scientific research?

Radiation diode detectors are commonly used in scientific research for various purposes, such as radiation dosimetry, medical imaging, and environmental monitoring. They are also used in industries such as nuclear power and healthcare for radiation safety and quality control. The accurate and precise measurements provided by these detectors make them an essential tool for studying and understanding the effects of ionizing radiation.

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