How to build fast visible light detector
Too bad you are a decade late. Sharp invented a 5mm Light Detector that spanned > 4 decades of visible light with a lens that matched the human eye CIE color-corrected. that didn't sell even so precise and cheap, even Vishay couldn't market it, so it went obsolete.  

There are others http://global.sharp/products/device/lineup/selection/pdf/opto_det201809_e.pdf

How fast??   3 to 5 us rise time

Or faster?

Keep in mind, Light sensors are current sources and high impedance so the lower the current and higher the impedance into some capacitance results in slower rise time.