Laser interference lithography as a tool for advanced nanostructures

Mark Hopkinson^, Yun Ran Wang, Im Sik Han.

Department of Electronic and Electrical Engineering, University of Sheffield, North Campus, Broad Lane. Sheffield S3 7HQ. United Kingdom

Abstract: We report on the application of nanosecond pulsed laser interference lithography for the formation of advanced semiconductor nanostructures.  We show that the technique is a powerful, cost effective and high throughput method for the formation of sub-micron periodic structures either directly on the growing semiconductor surface mass-transfer or by transfer to the grown surface via photoresist and etch.

In our direct laser interference processing approach, pulsed laser interference is applied directly to the MBE growth of semiconductor nanostructures in a wafer growth environment. We observe that the intense periodic pattern of UV light can influence diffusion at the wafer surface creating nucleation centers for self-assembly. Using this approach, we have demonstrated the formation of periodic arrays of semiconductor quantum dots with precision placement and excellent uniformity. The resulting structures are expected to be suitable to produce arrays of identical single photon emitters.

We will also describe the use of this indirect pulse laser interference for the surface structuring of conventional photonic devices such as photovoltaic solar cells and light emitting diodes. Through the generation of photonic band gap structures, we show we can improve solar absorption through the creation of broadband and wide angle antireflectance and to improve light extraction and coupling efficiency in light emitting diode structures.

Biography: Mark Hopkinson, born in Nottingham (UK), received his B.Sc degree from the University of Birmingham in 1985 and his Ph.D. from the University of Sheffield in 1990, both in Physics. After appointments as research associate and senior researcher he was appointed to a chair of Electronic Engineering at the University of Sheffield in 1998. His research work concerns the growth of semiconductor nanostructures by Molecular Beam Epitaxy and their exploitation in advanced devices. He has over 600 papers in this field. His recent work seeks to exploit in-situ laser interference lithography for the development of nanopatterned semiconductor structures.