Bandgap modification in GaInAs/InP quantum well structures using switched ion channelling lithography

A novel technique has been developed to lithographically modify GaInAs/InP quantum well (QW) structures. 10 MeV ⁶⁹Ga³⁺ ions are implanted into a 40 nm InP/9 nm GaInAs/InP (100) substrate along the [100] direction. A 50 nm thick Au mask switches a fraction of the aligned ions into dechannelling trajectories. The dechannelled ions enhance the ion beam induced intermixing of the GaInAs QW with the surrounding InP cladding layers. Low-temperature photoluminescence (PL) was used to study bandgap modification of the GaInAs QW after implantation for a fluence range of 4 × 10¹¹-4 × 10^{13 69}Ga³⁺ ions cm^-2. A larger bandgap energy shift was observed with PL under the Au mask (28 meV) compared to areas not covered with the Au mask (12 meV). Furthermore, the integrated PL intensity was found to be lower in the masked areas, which is consistent with a greater defect concentration in the regions under the Au mask.