For a GaAs with bandgap Eg =1.4eV
Effective electron mass is 0.07*me
Calculate the energy of the ground (lowest) electron level in the conduction band with respect to the bottom of the conduction band.
Ea =Ec + h^2a^2 / 8*me*d^2
The Attempt at a Solution
As it was with respect to the conduction band bottom I only used the second part of the equation and as it was the lowest level I had a=1
Put it through Wolfram so you can see working
However the answer I was given as a solution was
4.36*10^-21 J ( 0.027eV)in the book
where as my result is 8.6*10^-21
Is there something wrong with my method?