A thermoelectric device having a channel portion which includes at least one channel layer made of a topological insulator material and having a top surface with at least one groove, wherein each side surface of each groove includes a conducting zone with a pair of topologically protected one-dimensional electron channels. Each channel layer includes at least one n-region and at least one p-region which are alternatingly disposed and extend from a first end to a second end of the channel layer, each n-region comprising at least one n-groove running from a first electrode at the first end to a second electrode at the second end and each p-region includes at least one p-groove running from a second electrode to a first electrode, wherein the first and second electrodes are alternatingly disposed to connect the p-grooves and n-grooves of neighboring regions, whereby all p-grooves and n-grooves are connected in series.