| 摘要 |
In the case of a thick light-absorbing layer 2 , a phenomenon of a decrease in the time resolution occurs. However, when the thickness of the light-absorbing layer 2 is limited, a portion of low electron concentration in one electron group is cut out, and hence overlap regions of adjacent electron concentration distributions decrease. Therefore, by shortening the transit time necessary for the passage of electrons, regions of overlapping electron distributions due to diffusion can also be suppressed. Furthermore, the strength of an electric field within a light-absorbing layer can be increased by thinning the light-absorbing layer. Therefore, the time resolution of infrared rays can be remarkably improved by a synergistic action of these effects. If it is assumed that the time resolution is 40 ps (picoseconds), for example, when the thickness of a light-absorbing layer is 1.3 mum which is nearly equal to the wavelength of infrared, then a possible time resolution is 7.5 ps when this thickness is 0.19 mum.
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