Effects of Ga deposition rate and Sb flux on morphology of GaSb quantum dots formed on GaAs

Abstract

We investigate the effects of Ga deposition rate (RGa) and Sb flux (PSb) on the morphology of GaSb quantum dots (QDs). GaSb QDs are formed on GaAs at 420 °C by Stranski‐Krastanov (SK) mode under various conditions of RGa (0.13‐0.73 monolayer (ML)/s) and PSb (1.0‐4.2 × 10‐7 Torr). An atomic microscope study shows that the density nQD of GaSb QDs is markedly affected by PSb and RGa; no (or few) QDs are formed at high RGa (∼ 0.73 ML/s) and at low PSb (≤1.2 × 10‐7 Torr). As RGa (PSb) increases, nQD first increases and then decreases. nQD reaches its maximum (∼1 × 1011 cm‐2), when the V‐III ratio is about 3.6. We also analyze the experimental data by using a rate equation model and discuss the dependences of nQD on RGa and PSb.