Quantum wires and quantum dots on high-index substrates

The unique self-organizing growth mechanisms on planar and patterned high-index substrates leading to quantum wire and quantum dot arrays with unprecedented structural and electronic properties are reviewed. On not intentionally patterned substrates these are nanometer-scale self-faceting in molecular-beam epitaxy (MBE) and metalorganic-vapor-phase epitaxy (MOVPE), most prominent for GaAs (3 1 1)A planes, and the formation of buried (InGa)As quantum disks on GaAs (3 1 1)B substrates in MOVPE. On intentionally patterned GaAs (3 1 1)A substrates the self-limiting formation of a fast growing mesa sidewall in MBE is highlighted which reveals a high flexibility for the fabrication of dense arrays of quantum wires, dot-like nanostructures, and coupled wire-dot arrays with superior control of nanostructure size and position. A new dimension in nanostructure formation is introduced by combining natural self-faceting on GaAs (3 1 1)A substrates with patterned growth in atomic hydrogen assisted MBE producing quantum-dot arrays with minimized size fluctuations.