Controlled Assembly and Dispersion of Strain-Induced InGaAs/GaAs Nanotubes

Abstract

Abstract-Group III-V semiconductor nanotubes (SNTs) are formed when strained planar bilayers are released from the substrate. Compared to other nanotechnology building blocks, one of the main advantages of SNTs is the capability of precise positioning due to the top-down fabrication approach. In this letter, we demonstrate large-area assembly of ordered arrays of In x Ga 1 −x As/GaAs nanotubes and the dispersion of their freestanding form into solution and onto foreign substrates. In addition, we systematically investigate the crystal orientation dependence of rolling behavior using a wheel configuration, which serves as a guide for assembly homogeneity. Theoretical and experimental evaluations of tube diameters are also discussed.

Strain induced semiconductor nanotubes: from formation process to device applications

“…Furthermore, the ordered SNT array formation can be scaled to whole wafers, since the processing method used is compatible with existing micro-electronic processing technology. A small degree of inhomogeneity in tube diameter along and between tubes in such arrays has been observed [22,47]. The precision in lithography patterning alignment can affect the diameter distribution.…”

“…Shown in figure 6(b) is the result of the In 0.3 Ga 0.7 As/GaAs bilayer released from the (0 0 1) GaAs substrate using such a wheel pattern [47]. The centre image shows all pads around the wheel while the zoomed in image for each pad is laid out in the outer periphery.…”

Tuning the photoluminescence characteristics with curvature for rolled-up GaAs quantum well microtubes

“…The bottom up aspect is the epitaxial growth of the strained layers with desired composition and thickness, which determines the tube diameter ͑from a few nanometers to a few tens of microns͒. [6][7][8] The top-down aspect is the definition of the mesa to expose sidewalls of the epitaxial film for lateral etching of the sacrificial layer in order to release the strained layer from the substrate. This mesa determines the tube location, orientation, and dimension ͑length, width, and number of rotations͒.…”

“…As a result, self-rolling tubular micro-and nanostructures can be assembled in large arrays with uniform diameters and exceptional spatial placement controllability through postgrowth lithography, as demonstrated previously. 4,7 They can also be dispersed and transfer-printed to other substrates. 3 Various types of active structures such as quantum well ͑QW͒ and quantum dots can be embedded in the tube wall by using the strained In x Ga 1−x As layer as a wrapper while keeping the rest of the layers either lattice matched to the substrate or involving discrete structures.…”

Optically pumped rolled-up InAs/InGaAsP quantum dash lasers at room temperature

“…Such optical tube cavities are formed when strained nanomembranes are selectively released from the host substrate. They can be readily transferred to Si or other foreign substrates and have therefore emerged as a highly promising approach to realize high performance lasers on Si [6,10,11]. In addition, the threedimensionally confined optical modes can be precisely tailored by varying the tube diameter, wall thickness, and surface geometry using standard photolithography process [12,13].…”