A multi-gate transistor and a method of forming a multi-gate transistor, the multi-gate transistor including a fin having an upper portion and a lower portion. The upper portion having a first band gap and the lower portion having a second band gap with the first band gap and the second band gap designed to inhibit current flow from the upper portion to the lower portion. The multi-gate transistor further including a gate structure having sidewalls electrically coupled with said upper portion and said lower portion and a substrate positioned below the fin.