To solve the problem of crystallinity in an imaging apparatus utilizing a band gap.

The band gap is controlled by changing the composition ratio of a mixed crystal system of a compound semiconductor. For example, the absolute value of lattice mismatching Δa is made small by using an AlGaInP-based mixed crystal, an SiGeC-based mixed crystal, a ZnCdSe-based mixed crystal, and an AlGaInN-based mixed crystal. For example, Ge having a lattice constant larger than that of Si is mixed with SiC, thus reducing the absolute value of the lattice mismatching, and increasing crystallinity. At least one superlattice layer having a thickness of approximately 10 nm or smaller is formed at the interface of Si and SiC, or Si and SiGeC-based layer, thus increasing crystallinity further.

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