In this work we obtain the exact analytical scattering solutions of a
particle (electron or hole) in a semiconductor double heterojunction -
potential well / barrier - where the effective mass of the particle varies with
position inside the heterojunctions. It is observed that the spatial dependence
of mass within the well / barrier introduces a nonlinear component in the plane
wave solutions of the continuum states. Additionally, the transmission
coefficient is found to increase with increasing energy, finally approaching
unity, whereas the reflection coefficient follows the reverse trend and goes to
zero.Comment: 7 pages, 6 figure
