Site-specific growth of oriented ZnO nanocrystal arrays.

Rekha Bai,Jori Lemettinen,Veer Dhaka,Dinesh K Pandya,Harri Lipsanen,Christoffer Kauppinen,Vladislav Khayrudinov,Sujeet Chaudhary

doi:10.3762/bjnano.10.26

Rekha Bai, Jori Lemettinen + Show 6 more

Open Access

https://doi.org/10.3762/bjnano.10.26

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Abstract

We report on the growth of ZnO nanocrystals having a hexagonal, prismatic shape, sized 700 nm × 600 nm, on bare indium tin oxide (ITO) substrates. The growth is induced by a low ion flux and involves a low-temperature electrodeposition technique. Further, vertically aligned periodic nanocrystal (NC) growth is engineered at predefined positions on polymer-coated ITO substrates patterned with ordered pores. The vertical alignment of ZnO NCs along the c-axis is achieved via ion-by-ion nucleation-controlled growth for patterned pores of size ≈600 nm; however, many-coupled branched NCs with hexagonal shape are formed when a patterned pore size of ≈200 nm is used. X-ray diffraction data is in agreement with the observed morphology. A mechanism is proposed to interpret the observed site-specific oriented/branched growth that is correlated to the pore size. As ordered NC arrays have the potential to generate new collective properties different from single NCs, our first demonstration of a cost effective and facile fabrication process opens up new possibilities for devices with versatile functionalities.

Highlights

Metal oxide semiconductor nanostructures are quite interesting in terms of the basic growth mechanism involved in their fabrication, and due to the large number of applications based on them in the field of nanoscale optoelectronics [1,2,3,4]
In contrast to the S600 sample, wherein crystals with c-axis normal to the indium tin oxide (ITO) substrate are formed, many coupled branched ZnO NCs with hexagonal shape are revealed when the pore size was decreased to ≈200 nm, demonstrating the significant effect of pore size on the morphology of ZnO NCs
It may be pointed out that the overall morphology of the NCs is changed in S200, the periodicity observed is maintained in both S600 and S200 samples as per the pore pattern planned on the ITO substrate

Summary

Introduction

Metal oxide semiconductor nanostructures are quite interesting in terms of the basic growth mechanism involved in their fabrication, and due to the large number of applications based on them in the field of nanoscale optoelectronics [1,2,3,4]. We demonstrate the growth of hexagonal faceted self-assembled twin ZnO NCs on bare indium tin oxide (ITO) substrate via a facile low temperature electrodeposition technique that has the potential of yielding good crystal quality with a variety of possible nanoarchitectures under low ion-flux conditions.

Results

Conclusion