Compound semiconductor nanotube materials grown and fabricated
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A new GaAs/InGaAs/InGaP compound semiconductor nanotube material structure was designed and fabricated in this work. A thin, InGaAs-strained material layer was designed in the nanotube structure, which can directionally roll up a strained heterostructure through a normal wet etching process. The compound semiconductor nanotube structure was grown by gas-source molecular beam epitaxy. A good crystalline quality of InGaP, InGaAs, and GaAs materials was obtained through optimizing the growth condition. The fabricated GaAs/InGaAs/InGaP semiconductor nanotubes, with a diameter of 300 to 350 nm and a length of 1.8 to 2.0 μm, were achieved through normal device fabrication.
Keywordscompound semiconductor nanotubes gas-source molecular beam epitaxy GaAs/InGaAs/InGaP.
Compound semiconductor nanotubes are a new field that has only caught limited attention. Recently, compound semiconductor nanotubes have been applied in improving existing biological and medical devices and in developing novel devices for gene and drug delivery [1, 2, 3, 4, 5]. Traditional technologies fail to produce microtubes with diameters smaller than 10 mm . Previously, a new fabrication method for precise, single-crystal semiconductor micro- and nanotubes was proposed and realized [7, 8]. The approach is based on self-rolling of a thin, strained epitaxial heterofilm during its detachment from the substrate in a chemically treated system 'epitaxial heterofilm/sacrificial layer/substrate.' In this technology, the tube diameter can be precisely controlled. This allows feasible large-area assembly and integration with the existing semiconductor technology while maintaining the control of nanotube size and heterojunction formation in the tube wall.
In this work, GaAs/InGaAs/InGaP compound semiconductor nanotube structure materials were designed and grown successfully by gas-source molecular beam epitaxy [GSMBE]. High-quality GaAs, InGaAs, and InGaP epi-layers were obtained through optimizing the growth condition. The fabricated GaAs/InGaAs/InGaP semiconductor nanotubes, with a diameter of 300 to 350 nm and a length of 1.8 to 2.0 μm, were achieved through normal device fabrication. The experimental results indicate that the GaAs/InGaAs/InGaP compound semiconductor nanotubes have a good application prospect.
Schematic of the GaAs/InGaAs/InGaP compound semiconductor nanotubes' epitaxial layer structure
Inner wall layer
GaAs (N = 2E18)
Semi-insulating GaAs substrate
Results and discussion
An X'pert high-resolution X-ray diffractometer [XRD] (Philips, Amsterdam, The Netherlands) was used to evaluate the crystalline quality of the epi-layer and its lattice mismatch with the GaAs substrate. Through optimizing the growth condition, high-quality lattice-matched InGaP/GaAs and mismatched In0.2Ga0.8As/GaAs heterostructures were obtained.
Etching reagent of GaAs, InGaAs, and InGaP materials
Etching reagent (molar ratio)
GaAs and InGaAs
Citric acid/H2O2 = 1:1
H3PO4/HCl = 3:1
In summary, GaAs/InGaAs/InGaP compound semiconductor nanotube structure materials were designed and grown successfully by GSMBE. High-quality GaAs, InGaP, and InGaAs epitaxial materials were obtained successfully by optimizing the growth conditions. In the fabrication process, the photo-etched mask patterns were designed and compound semiconductor nanotube structure materials were fabricated by normal photolithography and wet etching process. The compound semiconductor nanotubes with a diameter of 300 to 350 nm and a length of the 1.8 to 2.0 μm were achieved. The experimental results indicate that the GaAs/InGaAs/InGaP compound semiconductor nanotubes have a good application prospect.
This work was supported by the National Basic Research Program of China (no. 2010CB327502).
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.