I. Kostis – G. Papadimitropoulos

An atomic layer deposition (ALD) system was designed and developed equipped with a hot wire (HW-ALD) permitting the separate heating of the gas phase.

(a)	(b)
Fig.1. Photo of the HWALD system that was developed. The reactor and various electronic sub-systems are shown left while on the right a part of the gas line.

Except of “classical” depositions, heating of the wire only at a pressure of the order of 0,1-1 Torr, under certain N2 or under H2 deposits composed of stoichiometric or sub-stoichiometric oxides of the metallic wire are obtained. More precisely, a native oxide is grown on the surface of every wire. If the vapor pressure of this oxide is higher than that of the metal at a specific temperature, heating the wire produces a vapor of oxides which is deposited on a cold substrate. W and Mo wires were used and films with composition described by the formula MOx (where M: W or Mo and x=3 for stoichiometric and x<3 for sub stoichiometric) were deposited. The above films were used in organic light emitting diodes (OLEDs) and organic photovoltaic devices (see Project I 1, Functional molecular materials for lithography and organic-molecular electronics).