  We have theoretically investigated a generation of entangled photons from
biexcitons in a semiconductor film with thickness in nano-to-bulk crossover
regime. In contrast to the cases of quantum dots and bulk materials, we can
highly control the generated state of entangled photons by the design of
peculiar energy structure of exciton-photon coupled modes in the thickness
range between nanometers and micrometers. Owing to the enhancement of radiative
decay rate of excitons at this thickness range, the statistical accuracy of
generated photon pairs can be increased beyond the trade-off problem with the
signal intensity. Implementing an optical cavity structure, the generation
efficiency can be enhanced with keeping the high statistical accuracy.
