Reentrant Behavior of the Density vs. Temperature of Indium Islands on GaAs(111)A

Abstract

We show that the density of indium islands on GaAs(111)A substrates have a non-monotonic, reentrant behavior as a function of the indium deposition temperature. The expected increase in the density with decreasing temperature, indeed, is observed only down to 160 ∘C, where the indium islands undertake the expected liquid-to-solid phase transition. Further decreasing the temperature causes a sizable reduction of the island density. An additional reentrant increasing behavior is observed below 80 ∘C. We attribute the above complex behavior to the liquid–solid phase transition and to the complex island–island interaction which takes place between crystalline islands in the presence of strain. Indium solid islands grown at temperatures below 160 ∘C have a face-centered cubic crystal structure.

Telecom-wavelength InAs QDs with low fine structure splitting grown by droplet epitaxy on GaAs(111)A vicinal substrates

“…In order to study μ-PL individual QDs, it is necessary to create nanostructures with a density of 10 8 -10 9 cm -2 . From the previous work [32] we have determined that In droplets, directly deposited on a vicinal GaAs(111)A substrate at a temperature of about 400 °C, have the desired density. On the other hand, the majority of dots of sample E has hexagonal-like pyramidal shape (see the inset of Figure 2b) with a height of 15.9±3.3 nm and width of 266±52 nm, measured also for 50 dots.…”

Strain Relaxation of InAs Quantum Dots on Misoriented InAlAs(111) Metamorphic Substrates

“…The samples studied in this work were grown on undoped semi-insulating GaAs(111)A substrates with a miscut of 2 towards [ 2] in a solid-source MBE. The use of vicinal wafers allows for a high growth rate of thick epitaxial layers (e.g., distributed Bragg reflector (DBR)) without incurring the formation of triangular hillocks that is typical on singular (111) surfaces [ 39 ]. The use of the [ 2] direction of a miscut and its angle value are caused by the good growth performance shown in our previous works [ 37 , 39 ]; After a 85 nm GaAs buffer layer had grown at °C with a growth rate of 0.5 ML/s, a 100 nm In Al As metamorphic barrier layer was deposited at °C with the growth rate of 0.5 ML/s.…”

“…The use of vicinal wafers allows for a high growth rate of thick epitaxial layers (e.g., distributed Bragg reflector (DBR)) without incurring the formation of triangular hillocks that is typical on singular (111) surfaces [ 39 ]. The use of the [ 2] direction of a miscut and its angle value are caused by the good growth performance shown in our previous works [ 37 , 39 ]; After a 85 nm GaAs buffer layer had grown at °C with a growth rate of 0.5 ML/s, a 100 nm In Al As metamorphic barrier layer was deposited at °C with the growth rate of 0.5 ML/s. Then, metallic indium was supplied with the growth rate of 0.01 ML/s at 370 °C to reach 1 equivalent ML (S1, S3, S3 and S4) and 0.15 equivalent ML (S5 and S6).…”