Abstract: A light-emitting semiconductor device for emission of visible light of an n.sup.+ np.sup.+ junction type, especially a light-emitting diode and thin film electroluminescence device, is constituted of semiconductor films including elements belonging to Groups II and VI of the periodic table. The device is formed by laminating an n.sup.+ layer doped with n type impurity, an n layer which is a donor acceptor coactivated layer doped with n type and p type impurities and p.sup.+ layer doped with p type impurity wherein the device has an n.sup.30 np.sup.+ structure. The energy levels of the layers are such that the energy among n type impurity level E.sub.D.sbsb.1 of the n.sup.+ layer, n type impurity level E.sub.D.sbsb.2 and p type impurity level E.sub.A.sbsb.2 of the n layer, and p type impurity level E.sub.A.sbsb.1 of the p.sup.+ layer satisfies E.sub.D.sbsb.1 .ltoreq.E.sub.D.sbsb.2 and E.sub.A.sbsb.1 .ltoreq.E.sub.A.sbsb.2.