In this Letter, organic-inorganic quantum well containing organic heterojunction (OIQWOH) ITO\SiO2\MEH-PPV\Alq(3)\SiO2\Al has been fabricated. The electroluminescence of OIQWOH includes three different peaks under alternative-current voltages: blue emission (410 nm), green emission (510 nm) and orange emission (588 nm). The source of these three emissions was investigated. Moreover, it was found that the permittivity confinement effect and the quantum size effect can obviously affect the optical and electrical properties of OIQWOH. Mixed excitation was observed in OIQWOH structure under alternating-current applied voltages by studying its brightness oscillogram. (c) 2005 Elsevier B.V. All rights reserved.