ELECTRONS IN LATERALLY PERIODIC NANOSTRUCTURES

This chapter discusses the effects of artificially generated periodic potentials on quasi-two-dimensional (2D) electron systems in semiconductors resulting in superlattice phenomena or, in the extreme case of tight-binding superlattice potentials, in arrays of quasi-one-dimensional (1D) quantum wires or quasi-zero-dimensional (0D) quantum dots. Proper preparation techniques are crucial for precise control of the superlattice potential that patterns the originally 2D electron system in the semiconductor. Methods of lateral patterning may be classified into lithographic techniques and maskless techniques. Litographic techniques, in which the periodic structures are defined as a replica of a mask, take advantage of resist materials sensitive to exposure with particle or radiation beams. With the mask pattern on the crystal surface, various fabrication processes can be employed to transfer the geometry of the resist mask to the electron system. Slightly modified versions of the depletion gate technique were used later to induce laterally periodic density modulations or isolated arrays of electron channels for transport, optical, and capacitance measurements. © 1992, Academic Press Inc.