Band Gap Energy Of Germanium At Room Temperature

The energy is plotted as a function of the wavenumber k along the main crystallographic directions in the crystal since the band diagram depends on the direction in the crystal.

Band gap energy of germanium at room temperature. For an alloy the temperature dependent bandgaps of the constituents a and b are calculated first the bandgap and the energy offset are then calculated depending on the material. E γ 1 0 89 5 82 10 4 t 2 t 296 ev effective density of states in the conduction band. As the name implies this band is the forbidden one without energy. It has been shown that when ge is subjected to a tensile strain and a heavy n doping level room temperature photoluminescence pl can be greatly enhanced.

It also needs a small energy to lift the electrons from the valence band to the conduction band. 3 3 1 bandgap energy the bandgap or forbidden energy zone is one of the most important semiconductor parameters. A plot of the resulting bandgap versus temperature is shown in the figure below for germanium silicon and gallium arsenide. Various models define the temperature dependence of the bandgap energy in semiconductors e g.

The detailed energy band diagrams of germanium silicon and gallium arsenide are shown in figure 2 3 3. The forbidden energy gap in this material is quite small. The energy band diagrams of semiconductors are rather complex. The gap between valence band and conduction band is called as forbidden energy gap.

Comparisons of electroluminescence with photoluminescence spectra allow separating emission from intrinsic ge 0 8 ev and highly doped ge 0 73 ev. In solid state physics a band gap also called an energy gap is an energy range in a solid where no electronic states can exist. Electroluminescence stems from carrier injection into the intrinsic layer whereas. Room temperature direct band gap emission is observed for si substrate based ge p i n heterojunction photodiode structures operated under forward bias.

Therefore even at room temperature a minute quantity of valence electrons is lifted to the conduction band and constitute current conduction if a high electric field is applied. Fig 2 2 14 temperature dependence of the energy bandgap of germanium bottom black curve silicon blue curve and gaas top red curve. The valence electrons are so loosely attached to the nucleus that even at room temperature few of the valence electrons leave the band to be free. In graphs of the electronic band structure of solids the band gap generally refers to the energy difference in electron volts between the top of the valence band and the bottom of the conduction band in insulators and semiconductors.

Germanium ge is a group iv indirect band gap semiconductor but the difference between its direct and indirect band gap is only 140 mev. E g 0 742 4 8 10 4 t 2 t 235 ev where t is temperature in degrees k.