In the electronic device market, in addition to the high frequency application, GaN devices are expected for power device applications because a large dielectric breakdown voltage is presumed due to the wide band gap. But GaN devices are still in their early stages of development due to some technical problems including difficulty of preparing good substrates.
　This report considers the future market of electronic devices and optical devices, investigates the GaN market among them, and the energy saving effect.
　As a result, the following results were obtained. (1) The energy saving effect of GaN-based LEDs in the optical device market is huge mainly in lighting applications(200TWh), but already commercialized LEDs are sufficient for most applications. (2) Lasers and high-brightness LEDs as next-generation semiconductors are likely to make a big new market, but it is difficult to estimate the energy saving effect for new fields. (3) In the power device market, the potential of GaN device to contribute to saving energy by inverters is large (120TWh) from its physical properties. (4) However, since cost performance is important and it competes with SiC and Si-based semiconductors in the market, much work should be done for improvement in performance as well as cost reduction for the GaN devices to be accepted in the market to contribute to saving energy.
　Quantitative potential evaluation of GaN devices is a future task.