Investigation of the collective properties of excitons in polar semiconductors (ZnO)

Systematic investigations were made of the exciton--plasma collective effects in a semiconductor with polar binding. Two types of a bulk electron--hole liquid formed at high excitation intensities and relatively high temperatures (above that of liquid nitrogen). A quasi-two-dimensional liquid was observed on the surface of ZnO subjected to a low-dose argon ion treatment. The properties of a layer liquid, distinguishing it from the bulk form, were investigated. An analyisis was made of the phase diagrams for bound bulk and surface liquids