Journal of Luminescence 102–103 (2003) 44–47 Electron and hole intraband luminescence in complex metal oxides A. Lushchik a, *, F. Savikhin a , I. Tokbergenov b a Institute of Physics, University of Tartu, Riia Str. 142, 51014 Tartu, Estonia b Almaty State University, Dastyk 13, 480100 Almaty, Kazakhstan Abstract A fast (to3 ns) broadband and temperature-independent emission of NaNO 3 , BaMgAl 10 O 17 and SrMgAl 10 O 17 , excited under electron pulse irradiation, is interpreted as intraband luminescence (IBL). A separation of a hole component of the IBL allowed to estimate the width of the valence band in NaNO 3 , E v ¼ 3:8 eV. The intensity of IBL drastically decreases in the spectral region of 6.3–6.6 and 6.1–6.4 in BaMgAl 10 O 17 and SrMgAl 10 O 17 , respectively. This decrease is caused by the lowering of the density of the states at the edges of the valence band and, therefore, provides information on the value of E v : r 2002 Elsevier Science B.V. All rights reserved. Keywords: Fast intrinsic luminescence; Wide-gap oxides 1. Introduction Highly efficient intrinsic and impurity emissions of wide-gap inorganic materials, such as lumines- cence of impurity ions, exciton emission and crossluminescence, have found wide fields of application. The emission with a relatively low efficiency, the so-called intraband luminescence (IBL) connected with the radiative transitions of hot electrons (e-IBL) and hot holes (h-IBL) between the levels of the conduction band or the valence band of a crystal, respectively, has not been sufficiently studied. The e-IBL is mainly studied in alkali halides [1] and the h-IBL in some metal oxides [2]. Under high-energy irradiation of materials, the width of an IBL spectrum is limited by the process of multiplication of electronic excitations, the threshold of which is determined by the value ratio of the energy gap E g and the width of the valence band E v [3]. As a consequence of a high probability of non-radiative transitions between the levels inside the band, the duration of IBL is about 1 ps, the spectrum of IBL extends over the whole transparency region and the intensity of IBL strongly depends on the width of the band, where intraband radiative transitions take place [1]. Therefore, the integral yield of IBL in the materials investigated varies from 10 3 to 5  10 6 eV/eV. In alkali halide crystals, E g cE v and the e-IBL with the spectrum width of about E g is mainly observed, whereas the intensity of the h- IBL is lower by 20–60 times [1]. In semiconductor materials, including ZnS, E g oE v ; the width of the IBL spectrum is about 2E g and the peculiarities of *Corresponding author. Tel.: +372-7-428-946; fax: +372-7- 383-033. E-mail address: luch@fi.tartu.ee (A. Lushchik). 0022-2313/02/$ - see front matter r 2002 Elsevier Science B.V. All rights reserved. PII:S0022-2313(02)00530-6