Conduction Energy Band for Intrinsic Silicon

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Homework Help Overview

The discussion revolves around calculating the conduction band energy level (E_c) for intrinsic silicon at room temperature (300K). Participants are exploring various methods and formulas related to semiconductor physics, particularly focusing on the energy band structure of silicon.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to find alternative methods or resources for calculating E_c, questioning the definitions of E_c and E_f, and discussing the relationship between these energy levels and the band gap (E_gap).

Discussion Status

The conversation includes attempts to clarify the original poster's goals, with some participants providing insights into the definitions of energy levels in intrinsic semiconductors. There is an ongoing exploration of different approaches to understanding the conduction band and electron density calculations.

Contextual Notes

Participants note the lack of specific resources in textbooks and the need for clarity on the definitions of E_c and E_f, as well as the relationship between these energies and the band gap. The discussion reflects uncertainty about the methods available for calculating these values.

Corneo
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I am trying to find a way to calculate the Ec for intrinsic silicon at room temperature. I can't seem to find anything in my textbook for that. I have searched on line and the closest thing I can find is

[tex]E_c = E_g + \frac {\hbar^2 k^2}{2m_e}[/tex]

I know what Eg = 1.12 eV for intrinsic silicon at room temp. However is there another way? Possibly a table or CRC?
 
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Corneo said:
I am trying to find a way to calculate the Ec for intrinsic silicon at room temperature. I can't seem to find anything in my textbook for that. I have searched on line and the closest thing I can find is

[tex]E_c = E_g + \frac {\hbar^2 k^2}{2m_e}[/tex]

I know what Eg = 1.12 eV for intrinsic silicon at room temp. However is there another way? Possibly a table or CRC?

Er... I don't quite understand what exactly it is what you want to do. Do you want to find the band width of the conduction band up to the vacuum level? Or do you want to "calculate" the band structure of silicon in particular? The latter isn't trivial, and will require something such as a linear combination of atomic orbital (lcao) technique.

Zz.
 
Sorry if I wasn't clear. Perhaps I should stake it like so.
I wish to calculate the electron density in the conduction band for intrinsic silicon at T = 300K.
The formula I found is
[tex]n = N_c exp\left [ -\frac {E_c - Ef}{kT}\right] \text { with } N_c = 2 \left( \frac {2 \pi m_e kT}{h^2}\right)^{3/2}[/tex]

But I don't know what Ec nor Ef is. How can I find out?
 
Corneo said:
Sorry if I wasn't clear. Perhaps I should stake it like so.
I wish to calculate the electron density in the conduction band for intrinsic silicon at T = 300K.
The formula I found is
[tex]n = N_c exp\left [ -\frac {E_c - Ef}{kT}\right] \text { with } N_c = 2 \left( \frac {2 \pi m_e kT}{h^2}\right)^{3/2}[/tex]

But I don't know what Ec nor Ef is. How can I find out?

In an intrinsic semiconductor, Ef is the fermi energy and sits right in the middle of the band gap. Ec and Ev are the energy of the bottom of the conduction band and the energy of the top of the valence band, respectively.

This means that Ec - Ev = Egap. It also means that since Ef is right in the middle of the gap, Ec - Ef = Egap/2

[sorry, too lazy to do LaTex]

Zz.
 

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