A review of many-body effects in exciton ensembles in semiconductors is given with the emphasis on two-dimensional systems: structures with single and double quantum wells and with quantum microcavities. The Bose–Einstein condensation effect, an accumulation of a macroscopic number of excitons in the ground state of the system, is discussed. The known prohibition on condensation in low-dimensional systems can be lifted due to the disorder resulting from the chaotic potential. Manifestations of the finite exciton lifetime and, correspondingly, of the nonequilibrium of the excitonic system caused by processes of excitons entering and leaving the condensate state are analyzed. Other collective phases of excitons, namely, two-dimensional crystals of dipolar excitons and an electron–hole liquid, formed as a result of interparticle interactions, are discussed.

对半导体中激子系综中的多体效应进行了回顾，重点是二维系统：具有单量子阱和双量子阱以及量子微腔的结构。讨论了玻色-爱因斯坦凝聚效应，即系统基态中大量激子的累积。由于混沌势导致的无序，可以取消已知的低维系统中对凝聚的禁令。分析了激子进入和离开凝聚态过程引起的激子有限寿命以及激子系统不平衡的表现。激子的其他集体相，即偶极激子的二维晶体和电子空穴液体，是由于粒子间相互作用而形成的，