I need to measure the red or green or blue component of a light source. Are there any resistor or diode with this specific capability? I found some diode with rgb filter, but i'd want to know if there are something more specific.
There are chips that already do what you want. There is really no need to build your own thing out of color filters and diodes.
Take a look at the TCS3103 or TCS3104 from AMS for example. They output three voltages which are proportional to the incoming red, green and blue light components.