Electron tunnelling in semiconductor heterostructures

A theory of electron tunnelling in GaAs---Ga1-xAlxAs---GaAs heterostructures is presented. The theory takes into account the different non-parabolic energy dispersion relations in the two materials. Calculated values of allowed energy levels are also presented for structures used in earlier experiments. Results of optical absorption experiments are found to agree with theory within 1 meV, but the results of double-barrier tunnelling experiments differ from theory by a factor of about 1.5