Disclosed herein are quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a quantum well stack; a plurality of first gates disposed on the quantum well stack; a plurality of pairs of spacers, each pair of spacers disposed on opposites sides of an associated first gate, wherein each spacer in a pair has a curved surface that curves away from the associated first gate; and a plurality of second gates disposed on the quantum well stack, wherein the curved surface of each spacer is adjacent to one of the second gates such that at least a portion of each second gate is shaped complementarily to the curved surface of an adjacent spacer.