ZNS-MN ELECTROLUMINESCENT FILMS PREPARED BY HOT WALL TECHNIQUE

Manganese-doped zinc sulfide electroluminescent (EL) films were prepared for the first time by a hot wall technique with Mn planar doping. Undoped and Mn-doped ZnS films on glass substrates exhibit preferred cubic (111) orientation at the substrate temperature of 280-degrees-C. The DELTA-2-theta value (full width at half-maximum) of the 111 reflection of the ZnS:Mn film in an X-ray diffraction pattern was found to be improved with an increase in Mn concentration and film thickness. By means of secondary ion mass spectroscopy (SIMS) and electron spin resonance (ESR) analyses, it was confirmed that this doping technique was very efficient in obtaining a homogeneous Mn2+ distribution which yielded highly luminescent EL devices. For an optimum device with double insulators of stacked Ta2O5/Al2O3 layers, the maximum luminance and efficiency at 1 kHz sinusoidal excitation were 3200 cd/m2 and 1.3 lm/W, respectively.