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Journal of Crystal Growth 275 (2005) e2367–e2369

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Growth and characterization of gallium nitride nanowire

Vipul Srivastavaa, V. Sureshkumarb, P. Puviarasub, K. Thangarajub,R. Thangavelb, J. Kumarb,�

aDepartment of Ceramic Engineering, Banaras Hindu University, Varanasi, IndiabCrystal Growth Centre, Anna University, Chennai-600 025, India

Available online 22 December 2004

Abstract

The present-day trend towards the development of nanostructures has resulted in several interesting material systems

with unique and, in some cases, novel properties. Gallium nitride nanowires and nanodimensional structures have been

realized using a simpler approach of vapour phase-assisted deposition.

GaN nanodimensional structures have been realized on (0 001) sapphire substrates by suitable surface treatment

procedure using ferrous salt. Growth has been carried out at the substrate temperature of 950 1C. A separate synthesis boat

was kept close to the growth substrate and the reaction of Ga to GaN was made in the close proximity of the substrate.

Experiments were carried out at different growth temperatures and also by varying the proximity conditions of the substrate.

The surface features reveal excellent distribution of nanostructures which are correlated with the growth conditions.

r 2004 Elsevier B.V. All rights reserved.

PACS: 81.05.Ea; 81.10.Bk; 81.07.De; 81.15.Gh; 97.64.Dz

Keywords: B1. Boron trioxide; B1. Gallium; B1. Gallium nitride (GAN); B1. Ferrous sulphate

1. Introduction

Gallium nitride is one of the most promisingsemiconductors for optical devices in the blue toultraviolet region [1]. GaN nanomaterials haveinteresting and potentially important applicationsas exemplary materials to new theoretical conceptsand for practical applications [2]. The promise ofUV photoconducting devices for optical/electronicnanoscale switching devices has been fulfilled.

e front matter r 2004 Elsevier B.V. All rights reserve

ysgro.2004.11.338

ng author. Tel./fax: +91 44 235 2774.

ss: marsjk@annauniv.edu (J. Kumar).

Such devices would be wonderful test beds forstudying quantum effects in one-dimensionalstructures. On the other hand, the growth oflarger diameter rods could be very useful foroptical devices and electronic applications [3].

2. Experiment

Nanowire synthesis has been reported by Heet al. [4]. One gram of pure metal gallium, 1 g ofgallium nitride powder and 10 g of B2O3 are mixed

d.

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4

5

V. Srivastava et al. / Journal of Crystal Growth 275 (2005) e2367–e2369e2368

in an alumina boat and it was placed in a quartzreactor. The quartz reactor is kept inside thedouble zone furnace. Sapphire (0 0 0 1) substratewas initially cleaned using ferrous sulphate andplaced near the alumina boat. The furnace washeated to 950 1C. Nitrogen gas was allowed to flowover the gallium surface from the start of theexperiment. After reaching a temperature of950 1C, liquid ammonia was placed in a bubbleracross the nitrogen gas tube from the inlet of thequartz reactor. Nitrogen gas was used as thecarrier gas to allow the ammonia molecule into thereaction zone. The outgoing ammonia was passedthrough a bubbler containing dilute sulphuric acidin order to neutralize the outlet gas species beforethey were released into the atmosphere [3].

10 20 30 40 50 600

1

2

3In

tens

ity

2 Theta

(102

)

Fig. 2. XRD spectrum of gallium nitride nanowire grown at

950 1C (growth duration is 2 h).

3. Results and discussions

Once the temperature in the system exceeds30 1C, the solid gallium metal becomes liquid andbegins to diffuse over the surface of the aluminaboat. At higher temperatures, the gallium vapourpressure becomes significant. During growth, someNH3 molecules adsorbed on the gallium surfacedissociate into N atoms and react with gallium toform GaN molecules on the sapphire substrate [5].N atoms can also recombine into N2 gas which willdesorb. Fig. 1 shows the XRD pattern of galliumnitride nanowire sample grown at the substrate

10 20 30 40 50 600

1

2

3

4

5

Inte

nsity

2 theta

(100

)(1

01)

(102

)

(110

)

Fig. 1. XRD spectrum of gallium nitride nanowire grown at

950 1C (growth duration is 1 h).

temperature of 950 1C, and the growth was carriedout for 1 h. At 32.4, 36.9, 48.2, 57.9 (2y values) weobtained the XRD peak corresponding to galliumnitride.From these 2y values the lattice parameter was

calculated as a ¼ 3.1852 A and c ¼ 5.1874 A,which are in good agreement with the alreadyreported values [3]. Gallium nitride has crystallizedin the hexagonal structure. Fig. 2 shows the XRDspectrum of gallium nitride nanowire sample

Fig. 3. AFM analysis of GaN nanowire grown at temperature

950 1C (magnification is 1.084mm).

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Fig. 4. AFM analysis of GaN nanowire grown at temperature

950 1C (magnification is 282.58 nm).

Fig. 5. AFM analysis of GaN nanowire grown at temperature

950 1C (magnification is 213.50 nm).

V. Srivastava et al. / Journal of Crystal Growth 275 (2005) e2367–e2369 e2369

grown at a temperature of 950 1C and the growthwas carried out for 2 h.AFM analysis was carried out on the gallium

nitride nanowire sample grown at a temperature of950 1C for 1 h. Fig. 3 shows the AFM image ofgallium nitride nanowire. From this figure, weobserved some surface irregularity. The dimensionof the nanowire varies depending upon theammonia flow rate. Figs. 4 and 5 are the AFMimages of GaN nanowires. From these figures thelength of the GaN nanowire is found to be2000 nm and the width is 40 nm.

4. Conclusions

Gallium nitride nanowire was successfullygrown using a simpler technique and was char-acterized using XRD and AFM.

References

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[2] M. He, et al., J. Crystal Growth 231 (2001) 357–365.

[3] M. Senthil kumar, P. Ramasamy, J. Kumar, J. Crystal

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[4] M. He, I. Minus, P. Zhou, S.N. Mohammad, J.B. Halpern,

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Appl. Phys. Lett. 77 (2000) 3731.

[5] M.A. Khan, Q. Chen, R. Askogman, J.N. Kuznia, Appl.

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