Concentration of minority carriers in a pn junction

In summary, the conversation is about calculating the majority and minority carrier concentrations in a p-n junction with doping concentrations of Na=1E18cm^-3 and Nd=1E16cm^-3. The equations ni^2=(npo)(Na) and ni^2=(Pno)Nd are used, with the result being npo=139.24 cm^-3 and pno=13924cm^-3 for the minority concentrations. The person is unsure if their calculations are correct due to the low values compared to the doping concentrations.
  • #1
jeffy
17
0

Homework Statement




A semiconductor p-n junction is fabricated where the doping concentration on the p and n sides of the junction is Na=1E18cm^-3 and Nd=1E16cm^-3 respectively. Given that ni=1.18E10cm^-3, T=300k calculate:

a) The majority and minority carrier concentrations in the neutral bulk regions on either side of the junction.

Homework Equations


ni^2=(npo)(Na) and ni^2=(Pno)Nd
where npo is the concentration of electrons in the p doped region and pno is the concentration of holes in the n region

The Attempt at a Solution


using the above equations i got npo=139.24 cm^-3 and 13924cm^-3 for the minority concentrations. I want to ask if i did this right because i think these concentrations are kinda low


thanks for reading
 
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  • #3
ya but is the set up correct, because 139.24cm^-3 is low comaring to 1.18E18cm^-3, but then again they are minority carriers
 

FAQ: Concentration of minority carriers in a pn junction

1. What is the definition of minority carriers in a pn junction?

The minority carriers in a pn junction refer to the electrons in the p-type region and holes in the n-type region, which are present in lower concentrations compared to the majority carriers (electrons in n-type and holes in p-type).

2. How is the concentration of minority carriers determined in a pn junction?

The concentration of minority carriers in a pn junction is determined by the doping levels of the p and n regions, as well as the temperature. Higher dopant concentrations and higher temperatures lead to higher concentrations of minority carriers.

3. Why is the concentration of minority carriers important in a pn junction?

The concentration of minority carriers is important because it affects the behavior of the pn junction. For example, a higher concentration of minority carriers can lead to increased recombination and a decrease in the junction's ability to conduct current.

4. How does the concentration of minority carriers change with an applied voltage in a pn junction?

When an external voltage is applied to a pn junction, the concentration of minority carriers near the junction boundary decreases. This is due to the electric field created by the applied voltage, which causes the minority carriers to diffuse away from the junction.

5. How does the concentration of minority carriers affect the performance of a pn junction in electronic devices?

The concentration of minority carriers plays a crucial role in the performance of a pn junction in electronic devices. It affects the junction's ability to switch between conducting and non-conducting states, as well as its speed and efficiency in transmitting signals. Therefore, controlling and optimizing the concentration of minority carriers is essential in designing efficient electronic devices.

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