A while ago I built an own scanning tunneling microscope. One of the biggest challenges was to gather and understand scatterd documentation and to find the right parts (both hard- and software).
To preserver this knowledge and make this technology more accessible I created a guide which can be accessed here:

• GitHub repo: https://github.com/lemonspurple/DIY-Scanning-Tunneling-Microscope
• Codeberg mirror: https://codeberg.org/lemonspurple/DIY-Scanning-Tunneling-Microscope

The sources that are contained in the repositories are a snapshot of what worked at the time and is tested as stable. You can find updated software and hadware in their respetive repos:

• Python GUI app used to controll the microscope: https://github.com/PeterDirnhofer/tkinter-usb-app
• Controller board (houses ESP32, controlls, etc.): https://github.com/PeterDirnhofer/KiCad_RTM_Adapterboard_v3_0
• Transimpendance amplifier (evens the signal out): https://github.com/PeterDirnhofer/KiCad_RTM_Tunnelling-Amp_v_2_0