FORMATION OF HIGH-DENSITY QUANTUM-DOT ARRAYS BY MOLECULAR-BEAM EPITAXY

Surface modification by atomic hydrogen homogenizes the distribution a nd reduces the size of self-organized quantum dots (QDs) grown hy mole cular beam epitaxy (MBE) and also improves their photoluminescence int ensity. Quantum dot arrays of InGaAs are obtained on GaAs(311)B by con ventional MBE. The size and the density are approximately 30 nm and 7 x 10(10)/cm(2). The ordered structure of QDs shows strong dependence o n the In content, and the arrays of the QDs begin to become disordered as the In content increases to more than 0.6. The formation of the do t array is induced by wavy surface instability. The dot array on GaAs( 311)B is metastable and disordered upon thermal annealing.