A wavelength-selective photo detector device includes a transparent upper electrode
including a capacitor, a first semiconductor layer disposed under the upper electrode,
an optical absorption layer disposed under the first semiconductor layer for absorbing
light to form pairs of electrons and holes, an amplification layer disposed under
the optical absorption layer for generating secondary electrons, a second semiconductor
layer disposed under the amplification layer, and a lower electrode disposed under
the second semiconductor layer and including an inductance coupled in parallel
with an external resistance. The photo detector improves the S/N ratio and filters
only light having a particular wavelength band.
