Si and C δ-doping of GaAs grown by metal organic vapour phase epitaxy for fabrication of nipi doping superlattices

The growth conditions for Si and C δ-doped nipi doping superlattices in GaAs have been optimised at the growth temperature of 630°C. We found that the Si δ-doping concentration can be significantly changed by δ-doping time over the range of 10¹²-10¹³ cm^-2 at the optimised gas flow velocity. The similar range of the free hole density in C δ-doped GaAs has also been obtained simply by varying the TMAl flow rate during the δ-doping step. The full compensation of free electron and hole density in the Si and C δ-doped nipis can be achieved by choosing proper Si δ-doping time and TMAl flow rate. Growth of one Si and C δ-doped nipi in GaAs was demonstrated. Apart from the well-known effect of photo-excitation intensity on the effective band gap energy, the time-resolved photoluminescence reveals that the photoluminescence peak wavelength significantly increases in the relaxation process of the photo-excited nipi doping superlattice.