The status and future of diamond thin film FED

Abstract

Abstract Field emission displays have emerged as a leading contender of low-power flat panel applications. As one of the promising field emission cathodes (FEC), diamond thin film has some unique advantages over its conventional microtip counterpart because of the superlative physical and chemical properties of diamond and the simplicity of cathode manufacturing. Over the last year, FEPET, Inc., one of the leading organizations in developing FEC, has made tremendous progress in its cathode emission performance, film processing, and understanding of the emission mechanism. Currently, an emission site density (ESD) of 2×10 5 sites per cm 2 and current density of 100 mA/cm 2 have been achieved at an extraction field of about 10 V/μm. We also developed a novel patterning process that allows emission patterning without applying any post-deposition processing to the film to degrade its emission properties. The improvement in film emission properties is found closely related to a diminishing diamond peak and a strongly accentuated graphitic or amorphous carbon shift in the UV-Raman spectra. High-resolution atomic force microscopy (AFM) analysis also showed an association of the emission sites with conductive–insulating–conductive regions of the surface. With the achievable ESD today, diamond film FEC can already find many practical applications such as low- to medium-resolution displays and backlights for liquid crystal display (LCDs). For high-resolution color displays, significant improvement in emission site density is still necessary, and a glass substrate with high-quality surface becomes indispensable. The use of high-temperature glass applied for polysilicon active matrix LCDs (AMLCDs) or a low-temperature diamond thin film deposition process needs, therefore, to be developed.