Many of Human-made and Natural materials utilize electrons and photons, and the behaviors of photons and electrons are key issues to realize novel future device structures. The microscopic understanding of those materials to the extent of quantum physics, electron physics, and so on, would result in the contribution to the future device concepts. We grow materials by MBE, and characterize its optical and electronic properties by various conventional and state-of-the-art techniques. Natural materials represented by the human body would use a lot of electron and photon interactions, too. The understanding of those behavior would help diagnostics of early stage cancers. The room temperature photoluminescence (which is a conventional method to characterize semiconductor materials) of human body, for example,. provides various useful information including early cancers. The research fields covers various materials and their electronic and optical structures.