A high efficiency electro-emission device (HEED) has been developed with a structure of Pt/SiO x /Si/Al on a thermally-oxidized Si substrate. The thicknesses of the SiO x and Si films were 400 nm and 5 µ m, respectively. Electron emission characteristics of the HEED are reported. It was found that the HEED has an electron-emission efficiency as high as 28% and a high brightness of 80 kcd/m2 using phosphor ZnS:Cu,Al. This high electron-emission efficiency was obtained in a range of applied voltage in which negative resistance occurred.

We developed an active matrix driving organic light-emitting diode (OLED) panel on a glass substrate using two organic thin-film transistors (OTFTs) per pixel, a switching OTFT and a driving OTFT. The OTFTs are bottom contact structures with the high-dielectric constant gate insulator tantalum oxide (Ta2O5, relative dielectric constant of 23) produced by anodization in ammonium adipate solution and with pentacene as the active layer. The W/L (where W and L are the OTFTs channel width and length, respectively) was 400 µm/10 µm for the switching OTFTs and 680 µm/10 µm for the driving OTFTs. The characteristics of the OTFTs were improved by treating the Ta2O5 surface with hexamethyldisilazane (HMDS), so that the field-effect mobility was 2.0×10-1 cm2 V-1 s-1 and the current on/off ratio was 105. A green phosphorescent dopant, tris(2-phenylpyridine)iridium [Ir(ppy)3], was used for the OLED layer. The panel had 8×8 pixels and the aperture ratio was 27%. We confirmed a 16-gray-scale representation and a luminance of 400 cd/m2.

By using organic thin‐film transistors with pentacene as the active organic layer, active matrix organic light emitting diode panel has been developed. The number of pixels in the panel is 8 × 8, and each pixel is driven by switching and driving transistors. We confirmed 16 gray scales representation by means of an analog driving method.

We developed a 3-in. organic thin-film transistor (OTFT) array with an ink-jetted organic semiconductor. All layers except electrodes were fabricated by solution processes. The OTFT performed well without hysteresis, and the field-effect mobility in the saturation region was 0.45 cm2 V-1 s-1, the threshold voltage was 3.3 V, and the on/off current ratio was more than 106. We demonstrated a 3-in. active-matrix organic light-emitting diode (AMOLED) display driven by the OTFT array. The display could provide clear moving images. The peak luminance of the display was 170 cd/m2.