Measuring method of incident light and sensor having spectroscopic mechanism employing it

A method for measuring incident light employing a semiconductor structure comprising an electrode film transmitting incident light and being applied with a gate voltage;

• a first diffusion layer for capturing electrons generated by the incident light, the first diffusion layer being disposed under the electrode film with an insulating film provided therebetween;
• a second diffusion layer for taking out electrons captured in the first diffusion layer to the outside, the second diffusion layer being disposed at one end of the first diffusion layer ;
• a first electrode that is connected to the second diffusion layer and that takes out the captured electrons to the outside;
• and a second electrode that is connected to another end opposing to the second diffusion layer disposed in the first diffusion layer and that establishes an electric potential of the first diffusion layer , wherein the gate voltage is varied, the depth from the surface of the first diffusion layer in which electrons are captured is varied on the basis of wavelength and intensity of the incident light, and a current indicating the quantity of the electrons is measured, wherein a light intensity Φ at a depth x from the surface of the first diffusion layer is determined on the basis that the light intensity is exponentially attenuated when light is incident on the first diffusion layer, the ratio of the intensity of the incident light absorbed to a depth W from the surface of the first diffusion layer, in which electrons are captured to the intensity of the incident light absorbed to the whole depth of the diffusion layer is determined, and a current generated to the depth W is determined, thereby measuring wavelength and intensity of the incident light.