[8p-S102-1~9] Korea-Japan Applied Physics Symposium "quantum materials & devices and advanced semiconductors"

1:00 PM - 1:30 PM JST(4:00 AM - 4:30 AM UTC)English Presentation

[8p-S102-1] Growth of Semiconductor type-II Quantum Nanostructures by Droplet Epitaxy

〇Jong Su Kim¹, Jin Dong Song², Sang Jun Lee³ (1.Yeungnam Univ., 2.KIST, 3.KRISS)

Keywords:

Type-II Quantum Nanostructures

In this study, we fabricated InAs/GaSb type-II quantum nanostructures, including quantum wells (QWs), quantum dots (QDs), and quantum rings (QRs), using molecular beam epitaxy (MBE). The QW structures were grown using a conventional MBE epitaxial growth technique. In contrast, to form InAs QRs and QDs on GaSb substrates, the droplet epitaxy technique was employed. For the formation of QRs, indium droplets were crystallized under an As₂ beam equivalent pressure (BEP) of 1.5 × 10^-5 Torr at a substrate temperature (T_s) of 300 ^oC. Additionally, InAs QDs were fabricated at T_s below 100 ^oC under the same As₂ BEP conditions. The optical properties of the InAs/GaSb quantum nanostructures were investigated using photoluminescence (PL) and photoreflectance (PR) spectroscopy. To improve the optical quality of the low-temperature-grown (LTG) nanostructures, post-growth annealing was performed at temperatures ranging from 650 ^oC to 750 ^oC. PL measurements revealed that the PL intensity increased with higher annealing temperatures, indicating enhanced crystal quality. In the PR spectra, optical transitions corresponding to confined electron and hole states were observed. Additionally, Franz–Keldysh oscillations (FKOs) appeared above the GaSb bandgap, which are attributed to the interface electric field between the InAs and GaSb layers. These results demonstrate that high-quality InAs/GaSb quantum nanostructures can be successfully fabricated using the droplet epitaxy technique.