A transparent diode with high rectifying ratio using amorphous indium-gallium-zinc oxide/SiN{sub x} coupled junction

We introduce a transparent diode that shows both high rectifying ratio and low leakage current at process temperature below 250 °C. This device is clearly distinguished from all previous transparent diodes in that the rectifying behavior results from the junction between a semiconductor (amorphous indium-gallium-zinc oxide (a-IGZO)) and insulator (SiN{sub x}). We systematically study the properties of each junction within the device structure and demonstrate that the a-IGZO/SiN{sub x} junction is the source of the outstanding rectification. The electrical characteristics of this transparent diode are: 2.8 A/cm{sup 2} on-current density measured at −7 V; lower than 7.3 × 10{sup −9} A/cm{sup 2} off-current density; 2.53 ideality factor; and high rectifying ratio of 10{sup 8}–10{sup 9}. Furthermore, the diode structure has a transmittance of over 80% across the visible light range. The operating principle of the indium-tin oxide (ITO)/a-IGZO/SiN{sub x}/ITO device was examined with an aid of the energy band diagram and we propose a preliminary model for the rectifying behavior. Finally, we suggest further directions for research on this transparent diode.