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Energy band gap Eg of AlxGa1-xAs alloys

Contents  
   
 
Equation  
 

The energy band gap 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 from the 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 eq.(1)  
 
  In this equation the symbols have the following meaning: down
 
  Eg,dir direct energy band gap of AlxGa1-xAs for x < 0.45  
  x aluminum fraction of the AlxGa1-xAs alloy  
 
Numerical values  
 
  calculator calculator for Eg(x)   (uses javascript)  
 
 

Band gap Eg(x) and gap wavelength lg of AlxGa1-xAs alloys at 300 K.
The magenta and the blue curves correspond to the indirect and the direct gap, respectively.

 
 
 
x Eg(x)
(eV)
λg
(nm)
Graph Eg(x)
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
 
 
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