Rectification Mechanism of a P-type Oxide-based Metal–Insulator–Oxide Semiconductor–Metal Thin-Film Diode

An oxide thin-film diode (TFD) is required as a fundamental building block of the next-generation electronic circuit along with an oxide thin-film transistor (TFT). However, compared to recent developments in oxide TFTs, conventional oxide TFDs have limitations such as electrical instability, a low rectification ratio, and a narrow operating voltage range. Recently, a different type of TFD has been introduced by combining the electrical properties of an n-type oxide semiconductor with the phenomenon that charge carriers can be injected into the insulator. The new TFD with a metal–insulator–oxide semiconductor–metal (MIOSM) structure shows not only an excellent rectification ratio but also exhibits transparency. However, to guarantee the flexibility and scalability of the electronic circuit configuration, the development of a p-type oxide-based MIOSM TFD, as well as n-type, should be accomplished. Here, the first p-type nickel oxide-based TFD is reported. The p-type MIOSM TFD has a stable rectification ratio over 105, and the advantage of selectively narrowing or widening the operating voltage range from ±8 to ±80 V. Moreover, a transparent p-type MIOSM TFD was demonstrated. The new p-type oxide diode, which can be manufactured by the various existing thinfilm processes, is expected to contribute as an essential element of next-generation electronic circuits.