5th NTT-BRL school at NTT Atsugi R&D Center
November 24-27, 2009

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Progress in heterostructuring for high speed, power, and light
--- "State-of-the-art Devices using Group-III Nitride Semiconductors" ---
Dr. Toshiki Makimoto

    Group-III nitrides, such as GaN, AlN and InN, cover a wide range of bandgap energies from 6 eV to less than 1 eV, and therefore, these materials are expected to be used in broad areas.

    For example, compared with conventional transistors made of Si, GaAs, and InP, heterostructure field effect transistors (HFETs) and heterojunction bipolar transistors (HBTs) made of GaN and AlGaN will show higher power characteristics, which will be useful for wireless communication at a higher frequency range and power electronics at a lower frequency range.

    Examples of devices used in power electronics are AC-DC and DC-DC converter circuits for home electric appliances. Light emitting diodes (LEDs) made of GaN and AlGaN will emit short-wavelength light, which will be useful for lighting, sterilization and so on. On the other hand, when GaN and InGaN are used for optical devices, they will be candidates for full colour LED displays and quantum-well laser diodes (LDs) for optical fiber communications with higher performance.

    In this lecture, I will first talk about the characteristics of these group-III nitride semiconductors and their heterostructures. Then, I will discuss the potentials of electronic and optical devices using these materials and their heterostructures, compared with devices using conventional semiconductor materials such as Si, GaAs, and InP.