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Energy band gap Eg of AlxGa1-xAs alloys
Equation
The energy band gap Eg of AlxGa1-xAs alloys depends on the
aluminum content x. In the range of x < xc = 0.45 the gap is direct.
At x > xc the gap is indirect.
At room temperature (300 K) the dependency of the direct gap on aluminum content x can be calculated by the equation
(Sadao Adachi: "GaAs and Related Materials", World Scientific
Publishing Co. 1994)
Eg,dir (x) = 1.422 eV + x 1.2475 eV
In this equation the symbols have the following meaning:
- Eg,dir - direct energy band gap of AlxGa1-xAs for x < 0.45
- x- aluminum fraction of the AlxGa1-xAs alloy
Numerical values
calculator for Eg(x) (uses javascript)
Band gap Eg(x) and gap wavelength λg of AlxGa1-xAs alloys at 300 K.
| x | Eg(x) (eV) | λg (nm) |
|---|---|---|
| 0 | 1.422 | 872 |
| 0.05 | 1.48 | 838 |
| 0.10 | 1.55 | 800 |
| 0.15 | 1.61 | 770 |
| 0.20 | 1.67 | 743 |
| 0.25 | 1.73 | 717 |
| 0.30 | 1.80 | 689 |
| 0.35 | 1.86 | 667 |
| 0.40 | 1.92 | 646 |
| 0.45 | 1.98 | 626 |
| 0.50 | 2.00 | 620 |
| 0.60 | 2.02 | 614 |
| 0.70 | 2.05 | 605 |
| 0.80 | 2.07 | 599 |
| 0.90 | 2.11 | 588 |
| 1.00 | 2.16 | 574 |
- direct band gap
- indirect band gap