A field effect transistor device comprising: a base structure; a first heterostructure having a first layer located over said base structure, a second layer located over said first layer, and a first 2DxG channel located near the interface between said first and said second layers (112, 114); a second heterostructure having a third layer located over said second layer, a fourth layer located over said third layer, and a second 2DxG channel located near the interface between said third and said fourth layers (116, 118); a third heterostructure having a fifth layer located over said fourth layer, a sixth layer located over said fifth layer, and a third 2DxG channel located near the interface between said fifth and said sixth layers (132, 134); a source electrode located over said sixth layer and ohmically connected to each of said 2DxG channels; a drain electrode located over said sixth layer; a plurality of trenches located between said source electrode and said drain electrode, each of said trenches having a length, a width and a depth defining a first sidewall surface, a second sidewall surface and a bottom surface located therebetween, the bottom surface of each of said trenches being at or below the first 2DxG channel; and a crenelated gate electrode located over said sixth layer, said gate electrode located within each of said trenches, said gate electrode having a top and a bottom surface, the bottom surface of said gate electrode being in juxtaposition with the first sidewall surface, the bottom surface and the second sidewall surface of each of said trenches; characterized in that: all of the 2DxG channels of the device are either 2DEG channels or 2DHG channels; a delta doping material is located near the interface between the rexpective lower and upper layers of at least one of said heterostructures; and and said drain electrode is ohmically connected to each of said 2DxG channels. a base structure; a first heterostructure having a first layer located over said base structure, a second layer located over said first layer, and a first 2DxG channel located near the interface between said first and said second layers (112, 114); a second heterostructure having a third layer located over said second layer, a fourth layer located over said third layer, and a second 2DxG channel located near the interface between said third and said fourth layers (116, 118); a third heterostructure having a fifth layer located over said fourth layer, a sixth layer located over said fifth layer, and a third 2DxG channel located near the interface between said fifth and said sixth layers (132, 134); a source electrode located over said sixth layer and ohmically connected to each of said 2DxG channels; a drain electrode located over said sixth layer; a plurality of trenches located between said source electrode and said drain electrode, each of said trenches having a length, a width and a depth defining a first sidewall surface, a second sidewall surface and a bottom surface located therebetween, the bottom surface of each of said trenches being at or below the first 2DxG channel; and a crenelated gate electrode located over said sixth layer, said gate electrode located within each of said trenches, said gate electrode having a top and a bottom surface, the bottom surface of said gate electrode being in juxtaposition with the first sidewall surface, the bottom surface and the second sidewall surface of each of said trenches; characterized in that: all of the 2DxG channels of the device are either 2DEG channels or 2DHG channels; a delta doping material is located near the interface between the rexpective lower and upper layers of at least one of said heterostructures; and and said drain electrode is ohmically connected to each of said 2DxG channels. all of the 2DxG channels of the device are either 2DEG channels or 2DHG channels; a delta doping material is located near the interface between the rexpective lower and upper layers of at least one of said heterostructures; and and said drain electrode is ohmically connected to each of said 2DxG channels.