Parameter definitions for "fermi"
It's probably useful to look first at the special features page. You may also want to look at one of the general help files, Sliders, or
Graphs.
Inputs
- SLIDERS
- m_e: electron effective mass, in units of the free electron mass: determines the density of states at the bottom of the conduction band. (Restricted to values greater than .0001.)
- m_h: hole effective mass, in units of the free electron mass: determines the density of states at the top of the valence band.(Restricted to values greater than .0001.)
- Nd: donor concentration per cm^3. (Restricted to positive values.)
- Na: acceptor concentration per cm^3. (Restricted to positive values.)
- Eg0: energy gap at T = 0 K, in electron volts. (Restricted to positive values or zero.)
- dEg/dT: temperature coefficient of the energy gap, in electron volts per kelvin
- Ec-Ed: donor binding energy in electron volts. (Restricted to positive values or zero.)
- Ea-Ev: acceptor binding energy in electron volts. (Restricted to positive values or zero.)
- MENUS
- T/(1/T): the x-axis on both graphs can be switched between:
- T: temperature, and
- 1/T: inverse temperature.
- log/lin: the vertical scale for the densities plot can be chosen to be either:
- lin: linear, or
- log: logarithmic.
- BUTTONS
- copy densities: copies the densities graph for further manipulation: see Graphs.
- copy mu: copies the mu graph for further manipulation: see Graphs.
- presets: Takes you to a tear-off menu with which you may select the presets. For more details, see the preset item in the miscellaneous help file.
- configure: allows changing several system parameters not included in the main panel:
- min temperature: minimum temperature, in kelvin, for which carrier densities are calculated and plotted; (Restricted to positive values less than max temperature.)
- max temperature: maximum temperature, in kelvin, for which carrier densities are calculated and plotted; (Restricted to positive values greater than min temperature.)
- points in graph: number of discrete points for which densities are calculated and plotted: these points are uniformly spaced in 1/T. More points give higher resolution and fewer points faster response. (Restricted to positive integers less than 513.)
- revert: updates the listed configure parameters to the current values (which may have been changed by a preset command).
- close: closes the configure window.
- help: Opens the help system which you have already found!
- quit: Terminates "fermi".
Outputs
- DISPLAYS
- densities graph: plots the electron density (red) and the hole density (blue) as a function of temperature. Both are given as number per centimeter^3. Either the densities or their logarithm may be plotted according to the choice of the lin/log menu. They may be plotted either as a function of T or of 1/T, according to the choice from the T/(1/T) menu. (The red electron plot can overwrite the blue hole plot: if the densities are equal, only the red is visible.)
- mu graph: The five energies, conduction band energy (red), donor state energy (dashed black), chemical potential (green), acceptor state energy (dashed black), and valence band energy (blue), are plotted versus T or 1/T, according to the choice from the T/(1/T) menu.