[A+]광운대_물리전자2_요약과제_TH04(Chapter 5.2)

소개

"[A+]광운대_물리전자2_요약과제_TH04(Chapter 5.2)"에 대한 내용입니다.

목차

1) Summary of Sections
2) Explain of figure & Equations
3) Solve the problems

본문내용

1) Summary of Sections
5.2.1 The Contact Potential
The contact potential refers to the voltage formed when a p-type and n-type semiconductor are joined, as their Fermi levels align to reach thermal equilibrium. This potential acts as a barrier that prevents further diffusion of electrons and holes and serves as the source of the electric field within the depletion region.

This contact potential plays a key role in controlling current flow in a p-n junction diode:
- When an external voltage exceeds the contact potential, current flows easily.
- If the external voltage is smaller, current flow is weak or nearly blocked.
The contact potential is calculated using the following equation[1]:
V_0=kT/q ln(N_a/(〖n_i〗^2/N_d ))=kT/q ln((N_a N_d)/〖n_i〗^2 )
- N_a: p-type doping concentration // N_d: n-type doping concentration // n_i: intrinsic carrier concentration
- k: Boltzmann constant // T: absolute temperature // q: elementary charge

Depending on how the external voltage is applied, the behavior of the diode changes:
-> In forward bias, the contact potential is reduced, allowing current to flow easily.
-> In reverse bias, the contact potential increases, suppressing current flow.

5.2.2 Equilibrium Fermi Levels
In a p-n junction under thermal equilibrium, the Fermi level remains the same across both the p-type and n-type regions. This level represents the energy at which the probability of electron occupancy is 50%.[2]
In a p-type semiconductor, the Fermi level lies near the valence band, while in an n-type semiconductor, it is located close to the conduction band.

참고자료

· 밤도체. (2021.10.22). [반도체물성] PN Junction – Contact Potential. https://blog.naver.com/rlaqjawndsla/222545266382
· 포기금지. (2025.10.02). 반도체의 에너지 대역 구조, 페르미 준위, PN접합, 주요 반도체 소자 다이오드. 전기전자통신 임용 합격. https://blog.naver.com/250628-/224028340607
· Imhotep. (2024.06.14). Space Charge. Flying monkeys. https://blog.naver.com/imhotep/223478946998