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We investigate the effects of interfacial dielectric layers (IDLs) on the electrical properties of top-gate In-Ga-Znoxide (IGZO) thin film transistors (TFTs) fabricated at low temperatures below 200°C, using a target composition of In:Ga:Zn = 2:1:2 (atomic ratio). Using four types of TFT structures combined with such dielectric materials as Si3N4 and Al2O3, the electrical properties are analyzed. After post-annealing at 200°C for 1 hour in an O2 ambient, the sub-threshold swing is improved in all TFT types, which indicates a reduction of the interfacial trap sites. During negative-bias stress tests on TFTs with a Si3N4 IDL, the degradation sources are closely related to unstable bond states, such as Si-based broken bonds and hydrogenbased bonds. From constant-current stress tests of Id = 3 μA, an IGZO-TFT with heat-treated Si3N4 IDL shows a good stability performance, which is attributed to the compensation effect of the original charge-injection and electron-trapping behavior. [ABSTRACT FROM AUTHOR]

A blue light emitting diode based on wide band gap host for a blue fluorescence light emitting layer has been developed to fabricate hybrid white organic light emitting diode comprising of a fluorescence blue and a phosphorescence red light emitting layers. We have tested various wide band gap host materials including CBP, BAlq, and TcTa, and among them the device with TcTa host has shown good performance which could be attributed to tight exciton confinement. A phosphorescence red dopant (RD) has been introduced into BAlq layer to harvest triplet states of the fluorescence blue emission layer and we have succeeded in obtaining the balanced emission of the blue and the red emissions with high efficiency. The device showed the maximum external quantum efficiency of 16% at 0.1 mA/cm2 and 13% of external quantum efficiency with (0.29, 0.23) of CIE coordinates at 10 mA/cm2. [ABSTRACT FROM AUTHOR]