A Group III-Nitride (III-N) device structure is provided which comprises: a heterostructure having three or more layers comprising III-N material, an anode within a recess that extends through two or more of the layers, wherein the anode is in electrical contact with the first layer, a cathode comprising donor dopants, wherein the cathode is on the first layer of the heterostructure; and a conducting region in the first layer in direct contact to the cathode and conductively connected to the anode. Other embodiments are also disclosed and claimed.