We develop the model of micropillar photodetectors operated in the infrared domain. The model is based on an algorithm, which uses analytical methods and numerical simulation of Schrödinger equation, aimed at the calculation of the energy levels and wave functions of a semiconductor micropillar. We define the heterostructure as a combination of different semiconductor materials grown one on top of the other via epitaxial methods. The photon-detecting scheme is based on the fact that electrons in potential wells have different energies, and the transition between them (including tunneling) is induced by the absorption of a quantum of energy. The most probable optical transitions are verified; two particular transitions corresponding to the infrared range are demonstrated and relevant photo-current dependencies are discussed.