Photoluminescence (PL) and electroluminescence (EL) from single-crystal, n-type, Al-doped ZnSe (ZnSe:A1) electrodes have been studied. These samples exhibit both edge emission (k~a~ ~ 460 nm) and subbandgap emission when excited at several ultrabandgap wavelengths. The latter PL band is particularly intense, with a measured radiative quantum yield of -10 -I to 10-~; the transition appears to be at least partially self-activated (SA) in origin, based on previously reported PL data. Excited-state communication involving the two emissive states is inferred from time-resolved PL measurements. Stable photoelectrochemical cells (PEC's) can be constructed from n-ZnSe:A1 electrodes and aqueous diselenide or ditelluride electrolytes. Applied potential quenches both of the photoanodes' PL bands roughly in parallel. The extent of PL quenching is consistent with a dead-layer model previously used to describe quenching in Au-ZnSe Schottky diodes. When used as a dark cathode in aqueous, alkaline peroxydisulfate electrolyte, EL from ZnSe:A1 electrodes is observed. PL and EL spectral distributions are similar and indicate that the same emissive excited states are populated in the two experiments. Measured EL efficiencies, -10 -4 to 10 -6 at -2.2 and -1.8V vs. SCE, respectively, are much smaller than PL efficiencies. Possible sources of the discrepancies are discussed.Keen interest in photoelectrochemical cells (PEC's) has focused attention on the excited-state properties of the semiconductor electrodes which serve as the key element of these devices (1). We and others have studied photoluminescence (PL) and electroluminescence (EL) from a variety of II-VI and III-V semiconductor electrodes in an effort to determine the effect of PEC parameters on the solids' excited-state deactivation routes (2). In general, measured radiative quantum yields, ~br, of these materials have been small, -10-3-10 -~. We describe in this paper an electrode, n-ZnSe:A1, whose emission competes favorably (~br -10-1-10 -2) with other deactivation paths in stable, efficient PEC's. As observed with other semiconductor electrodes (3), the PL of n-ZnSe:A1 electrodes can be perturbed and EL initiated by interfacial charge-transfer processes. We show that PL quenching by applied potential is compatible with a dead-layer mode] used to describe such quenching in other PEC's (4, 5) and in Au-ZnSe Schottky diodes (6).) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.192.114.19 Downloaded on 2015-06-07 to IP

Das Photo‐ und Elektrolumineszenzverhalten einkristalliner n‐ZnSe:Al‐Elektroden werden untersucht.