This Phase I STTR project will investigate metal-organic chemical vapor deposition (MOCVD) to improve the performance of the blue-emitting layer used for full-color thin film electroluminescent (TFEL) displays. TFEL displays have demonstrated performance advantages compared with active matrix liquid crystal displays (AMLCD's) including wide viewing angle, wide operating temperature range, fast response time and inherent ruggedness. Commercialization of TFEL displays has been impeded by the insufficient luminance and efficiency of the blue-emitting EL phosphor films. MOCVD has demonstrated the capability of growing crystalline binary and ternary sulfide phosphors at temperatures less than 600 C, eliminating the need for costly high temperature substrates. Two approaches will be pursued for improving the blue EL material performance. The MOCVD process for he SrS:Ce phosphor will be optimized for luminance and emission intensity in the blue spectral region. The addition of codopants including Mn and Zn will be investigated to compensate for SrS lattice defects. Secondly, MOCVD of cerium doped cubic- GaS will be investigated as a potential new blue EL phosphor. The best performing blue-emitting material will be selected for process scale to commercial size TFEL display panels in Phase II. Potential commercial applications include full-color emissive flat panel displays for use in portable computers, industrial process control, instrument and medical electronics and telecommunications.
