Alright so recipe planner has silicon used only in solar panels, "electronic components", and a delivery cannon "recipe"
Solar panels recipe is:
Electronic circuits
Glass
Steel plate
Silicon x5
Electronic components recipe:
Glass
Plastic
Silicon x2
So it looks like there's possibility for more complexity with fiber-optics added to the circuitry recipe.
Plus I noticed you've added silicon to the recipe of concrete replacing stone brick.
The way K2 gets silica is through quartz, and the way they get quartz is through a filtration plant with sand and water.
Quartz is used in laser turrets and heat pipes.
This testing is with both K2 and SE so individually they may be different. I'll check SE by itself soon.