Self-assembled nanodrill technology based on droplet epitaxy growth was developed to obtain nanoholes on a GaAs(100) surface. In this technology, the gallium droplets act like “electrochemical drills” etching away the GaAs substrate beneath to give rise to nanoholes more than 10nm deep. The driving force of the nanodrill is attributed to the arsenic desorption underneath the gallium droplet at high growth temperatures and Ga-rich condition. This nanodrill technology provides an easy and flexible method to fabricate nanohole templates on GaAs(100) surface and has great potential for developing quantum dots and quantum dot molecules for quantum computation applications.

The CVD prepared V-MoS2 heterojunction photodetector exhibits excellent photoelectric performances in a wide broadband with high responsivity, large detectivity, and ultrafast response speed.

The nanopillar photonic-crystal cavities are arranged in arrays with varying pitch and diameter in order to fine tune the resonant wavelength and Q factor. Each array contains 4 rows and 6 columns of devices. In each row, the radius is varied between 0.15·a and 0.2·a (where a is the inter-pillar pitch). In each column, the inter-pillar pitch is varied between 324 nm and 342 nm. This variation in pitch corresponds to resonant wavelengths between 950 nm and 1000 nm according to the normalized frequency calculated from FDTD simulations (λ = a/ω n , where ω n = 0.342). Fig. S2 shows a dark-field optical microscope image at 50× magnification of an array in PDMS with the inset showing a single device at 150× magnification. Additional rows for other experiments (labeled A) are visible but not reported on in this paper.

A growth technique combining droplet epitaxy and molecular beam epitaxy (MBE) is developed to obtain a low density of InAs quantum dots (QDs) on GaAs nanoholes. This growth technique is simple, flexible, and does not require additional substrate processing. It makes possible separate control of the QD density via droplet epitaxy and the QD quality via MBE growth. In this letter the authors report the use of this technique to produce InAs QDs with a low density of 2.7×108cm−2 as well as good photoluminescence properties. The resulting samples are suitable for single QD device fabrication and applications.