We propose a new pixel design for the active matrix organic light-emitting diode (AMOLED) using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed pixel is composed of four switching TFTs, one driving TFT (DTFT), and one capacitor. The simulation results are performed by AIM-SPICE software. The error rate of OLED output current with V TH (threshold voltage) variation (0.3 V) and V dd power line drop by 1 V are improved to about 1.67% and 15%, respectively. Thus, the proposed pixel circuit can successfully overcome drawbacks suffered from DTFT threshold voltage deviation and IR-drop on power line.

This study discusses the impact of a p-GaN backgate structure on the DC characteristics of AlGaN/GaN HEMTs. AlGaN/GaN HEMTs with a p-GaN backgate layer showed reduction of leakage current and positive shift of threshold voltage while applying negative backgate bias. The shift of threshold voltage was 0.55 V, and reduction of off-state leakage current was 73.1% while backagte bias was -14 V. The on/off current ratio was in the range of 10 7 with backgate bias. It is possible to operate an AlGaN/GaN HEMT in both D-and E-modes with suitable epitaxial layer design using a p-GaN backagte structure.

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