71.45.Gm; 73.20.Hb; 73.21.Fg The study of valence band states in single p-type delta-doped quantum wells in ZnSe is performed using the Thomas-Fermi-Dirac approximation as framework for presenting an analytical expression for the Hartree-Fock potential. The results for the interband transition obtained in the calculation are compared with experimental values of photoluminescence showing E c À E v energy differences. In spite of the very scarce experimental information about these kinds of systems, it is possible to predict a very good agreement when this exchange-including simple model is applied.The achievement of p-type doping in ZnSe [1, 2] was crucial for the fabrication of II-VI-based blue-green laser diodes [3], but the insufficient p-conductivity of materials used for the waveguide, cladding, and contact layers resulted in large operating voltages for the laser diodes causing an undesirable extra heating of the devices.The first highly conductive p-type ZnSe was obtained by inserting heavily N-doped ZnTe single monolayers into undoped ZnSe layers [4]. The incorporation of Te, with an overall composition of only 9%, and a lattice mismatch as low as 0:6%, effectively enhances the incorporation rate and activity of N. The obtained hole concentration is 7 Â 10 18 cm À3 , which, together with a critical thickness of 500 A, gives a two-dimensional hole charge density p 2D ¼ 3:5 Â 10 12 cm À2 for the quantum well region.Theoretical studies of semiconducting p-type d-doped systems have been carried out in recent years in Si and III-V materials (see, for instance Refs. [5][6][7]). In particular, the Thomas-Fermi approximation has been applied, taking into account the combined effect of two and three hole bands [8,9].The inclusion of quantum mechanical many-body effects in the calculation of the electronic structure is widely considered in terms of the exchange and correlation potentials (see, for instance [10,11]). However, the discussion of the particularities of these effects in a hole gas is far more scarce. The Thomas-Fermi-Dirac approximation is the generalization of the Thomas-Fermi one when the effects of many bodies are considered through an exchange potential. This approximation is known in the literature and has been applied to free atoms [10]. In fact, for the case of neutral atoms, it does not lead to any self-consistent solution in which the electron density neither tends to zero at infinity nor indeed to a solution of finite radius in which the boundary density vanishes. Rather, when used in such a system, there are unavoidable discontinuities in the electron density at the boundary of the atom which is by all reasons unsatisfactory [10]. If we were to use the same approximation, but to describe the conduction band bending of a semiconductor quantum system caused by an electric charge in some
