Type II broken‐gap quantum wires and quantum dot arrays: A novel concept for self‐doping semiconductor nanostructures

A novel concept for creating self‐doping quantum wires and quantum dot arrays based upon the InAs‐GaSb material system is proposed. The unusual type II, broken‐gap band line‐up in this system allows charge transfer across the InAs‐GaSb interfaces. We employ a recently developed coupled band formalism to examine analytically the band structure of InAs‐GaSb quantum dots and wires. The analysis shows that appropriately engineered nanostructures which contain high free‐carrier densities are possible without intentional impurity doping. Quantum dots in this system behave as artificial quasiatoms, with ionization energy and valence determined by fabricationally determined parameters. Synthetic p‐(n‐)type semiconductors may therefore be formed from arrays of InAs(GaSb) quantum dots embedded in GaSb(InAs). InAs‐GaSb quantum wires are also investigated and found to exhibit self‐doping behavior. Possible fabrication schemes utilizing recently developed technologies are discussed.