CN1391237A

CN1391237A - Process for growing Ge nanoline by aluminium oxide template

Info

Publication number: CN1391237A
Application number: CN 02136111
Authority: CN
Inventors: 黄靖云; 叶志镇
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2002-07-17
Filing date: 2002-07-17
Publication date: 2003-01-15
Anticipated expiration: 2022-07-17
Also published as: CN1177351C

Abstract

A process for using alumina template to grow Ge nanowires includes such steps as preparing alumina template with multiple hexagonal cylinder holes by anodizing method, growing a gold layer as catalyst on the back of template, and growing Ge nanowires in gas-phase chemical deposition equipment, in which high-purity germane is used as growing gas source and nitrogen gas as protecting one, by reaction at 500-800 deg.C. Its advantage is controllable diameter and length.

Description

Method for growing germanium nanowires by using aluminum oxide template

Technical Field

The invention relates to a growth method of a semiconductor nanowire. In particular to a method for growing germanium nanowires by using an alumina template.

Background

Germanium (Ge) is an important semiconductor material for applications in high-speed microelectronics and infrared optics. Compared with Si, Ge has smaller electron effective mass, hole effective mass and lower dielectric constant, and the exciton Bohr radius (24.3nm) of bulk Ge is larger than that of bulk Si (4.9nm), so Ge has more remarkable quantum size effect. The size of Ge is reduced to nanometer level, and the energy band structure of the indirect band gap of Ge and the optical property of the material can be improved.

Due to the special properties and potential application prospects of the Ge nanowire material, researchers at home and abroad are exploring various methods for growing the Ge nanowire material. Hiroo Omi et al, which adopts a high-index surface method to grow Ge nanowires on Si (113) crystal surfaces, have consistent orientation of the prepared Ge nanowires, but have large distribution range of diameters and lengths. Another method for preparing Ge nano wire is to use photoetching technique to make pattern of nano wire on the substrate, then to grow Ge nano wire on the photoetching pattern.

Disclosure of Invention

The invention aims to provide a method for growing germanium nanowires by using an alumina template. The method can realize the controllability of the diameter and the length of the germanium nanowire and the ordering of the arrangement.

The method for growing germanium nanowire by using alumina template includes the steps of firstly preparing nano porous alumina template by adopting a common anodic oxidation method, enabling the nano-aperture holes on the template to be hexagonal column-shaped and vertically and orderly arranged in parallel with the template surface, then growing a layer of gold film serving as catalyst on the back surface of the nano porous alumina template by adopting an evaporation, sputtering or gold spraying method, then placing the gold-plated nano porous alumina template into a growth chamber of a chemical vapor deposition device, and using high-purity germane GeH₄(the purity is 99.995%) is a growth gas source, nitrogen is protective gas, and the germanium nanowires are grown by reaction at the temperature of 500-800 ℃.

The invention has the advantages that

1. The diameter and the length of the nano germanium wire are controllable, and the diameter of the nano germanium can be controlled by controlling the aperture of the nano porous alumina; the length of the nano germanium can be controlled by controlling the growth time, and the length can reach dozens of micrometers.

2. Arrayed nano germanium wires can be obtained.

Detailed Description

The invention is further illustrated below with reference to examples.

The embodiment adopts two-step anodic oxidation to prepare the nano porous alumina template, during the anodic oxidation, a lead plate is used as a cathode, an aluminum sheet with the purity of 99.99 percent is used as an anode, the aluminum sheet is firstly subjected to the processes of ultrasonic cleaning, annealing, alkaline degreasing, acid dipping and electrolytic polishing to obtain the aluminum sheet with a clean and smooth surface, the first step of anodic oxidation of the aluminum is carried out by adopting oxalic acid solution with the concentration of 0.3mol/L and the direct current voltage is constant at 40V at room temperature, and after 12 hours of oxidation, 8 percent CrO is used₃+6％H₃PO₄Etching the solution at 60 deg.C for 10 hr to remove the oxide layer, performing a second anodic oxidation step under the same conditions as the first step to form a porous alumina pore array, and applying HgCl₂Solution and H₃PO₄The solution removes the unoxidized aluminum to form a through alumina template. The nano-pore diameter on the template is generally 5-100 nm, in this case 30nm, and the pores are hexagonal columns and are arranged in parallel and in order perpendicular to the template surface. Then spraying a layer of gold film at room temperature on the back of the perforated nano porous alumina template to be used as a catalyst, and then putting the nano porous alumina template sprayed with gold into a growth chamber of a chemical phase deposition device; adjusting a temperature controller to ensure that the growth temperature is 720 ℃; simultaneous production of high purity germane (GeH)₄99.995% pure) gas was introduced into the growth chamber at a flow rate of 6 sccm. And growing the germanium nanowires by utilizing the high-temperature thermal decomposition reaction of chemical vapor deposition. The reaction equation is as follows:

and (4) finishing the growth process, and taking out the sample after the temperature is reduced to the room temperature.

In the growth process, nitrogen is used as protective gas, and residual germane stored in a mechanical pump of the chemical vapor deposition device is driven away from a pump cavity by utilizing the nitrogen at regular time.

Claims

1. The method for growing the germanium nanowires by using the alumina template is characterized by comprising the steps of firstly preparing the nano porous alumina template by adopting an anodic oxidation method, enabling holes with nano apertures on the template to be hexagonal columns and be vertically and orderly arranged in parallel with the surface of the template, then growing a layer of gold film serving as a catalyst on the back surface of the nano porous alumina template, putting the gold-plated nano porous alumina template into a growth chamber of a chemical vapor deposition device, taking high-purity germane as a growth gas source, and reacting and growing the germanium nanowires at the temperature of 500-800 ℃.

2. The method of claim 1, wherein the germanium nanowire is grown by using the alumina template, and the anode is oxidized by using a lead plate as a cathode and an aluminum plate with a purity of 99.99% as an anode.

3. The method of claim 1, wherein the gold film is grown on the back of the alumina template by evaporation, sputtering or spraying.

4. The method of claim 1, wherein the diameter of the nano-pores is 5 to 100 nm.