The flat-panel-display (FPD) market is experiencing rapid growth due to increased demand for portable computers, communication equipment, and consumer electronic products. In all of these applications, the display is the primary human interface that conveys information. The size of the flat-panel-display market is presently estimated to be $10 billion/year and is projected to grow to over $18 billion/year by 1998. Although most current FPDs utilize either passive- or active-matrix liquid-crystal-display (LCD) technology, electroluminescent (EL) displays and light sources, because of their solid-state construction and self-emissive characteristics, can provide improved performance for many demanding display applications. Thin-film electroluminescent (TFEL) technology has been demonstrated over a broad range of display sizes from 1-in. to 18-in. diagonal with resolutions from 50 to 1,000 lines per inch. Also, because of its unique solid-state characteristic, TFEL technology is well-suited to provide a fully integrated display with the light-emitting element and electronics fabricated on the same substrate. An example of a full-color TFEL display is shown in Figure 1.Thin-film electroluminescent display panels are finding increasing applications in the FPD marketplace due to several fundamental performance advantages over LCDs. These include wide viewing angle, high contrast, wide operating-temperature range, ruggedness, and long lifetime. Alternating-current (ac)-driven monochrome TFEL displays (ACTFEL displays) have become the most reliable, longest running devices on the market. Commercial ACTFEL display panels have operated for more than 50,000 hours with less than 10% luminance change, the equivalent of 25 working years.

Thin films of cerium-activated alkaline earth thiogallate were investigated for the fabrication of blue-emitting thinfilm electroluminescent (TFEL) devices. The films were prepared by RF sputtering from targets with composition: MI_~Ga2S4:Ce=, where M = Ba, Ca, St, and 0.01 -< x -< 0.1. Photoluminescent (PL) emission spectra showed matching peak wavelengths to those obtained from electroluminescent (EL) emission for each alkaline earth thiogallate film. The optimum cerium concentration for EL emission intensity for strontium and calcium thiogallate films was determined to be x = 0.04 and 0.06, respectively. The EL brightness measured for the calcium thiogallate devices was almost twice that measured for the strontium thiogallate devices. This brightness variation, however, is due mainly to the difference in the lumen equivalent of the emission intensity. The cerium concentration dependence of the PL emission spectra of the thiogallate films is substantially decreased compared with the respective powder material suggesting inhomogeneous cerium incorporation in the films. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.171.57.189 Downloaded on 2015-06-14 to IP

Photoluminescence ͑PL͒ and electroluminescence ͑EL͒ of blue and green SrS:Cu thin films prepared by atomic layer epitaxy and molecular beam epitaxy, and blue SrS:Ag,Cu,Ga thin films prepared by sputtering were studied in a temperature range of 80-320 K. Two bands are present both in the PL and EL spectra of SrS:Cu films. The low energy band ͑L band͒ at about 520 nm can be observed throughout the temperature range studied. The high energy band ͑H band͒ at about 460 nm is seen only at higher temperatures and it disappears at 80 K. Decay studies at 80 K reveal at least two types of centers having lifetimes of 100 and 17 s with a 10% variation. Several luminescence processes are proposed for further discussions. The L band may be attributed to the emission from an isolated Cu ϩ ion replacing the host Sr 2ϩ ion but at an off-center site, and it undergoes a redshift caused by aggregated Cu centers. The H band is tentatively described as due to the Cu ϩ ion at different site symmetry. Blue luminescence of SrS:Ag,Cu,Ga most probably originates from Ag ϩ pairs. There is no direct evidence of energy transfer from Cu ϩ to Ag ϩ but Cu does contribute to the EL.

In-situ stress monitoring has been employed during metalorganic chemical vapor deposition of AIGaN/GaN distributed Bragg reflectors (DBRs). It was found that the insertion of multiple AIN interlayers is effective in converting the tensile growth stress typically observed in this system into compression, thus alleviating the problem of crack generation. Crack-free growth of a 60-pair Alo.z5G~.75N/GaN quarter-wavelength DBR was obtained over the entire two-inch wafer; an accompanying reflectivity of at least 9970 was observed near the peak wavelength around 380 nm.-Email address: jhml@sandia.gov I

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