Research Area

  •        Semiconductor Lasers, e.g. DFB, VCSELs, VECSELs, coupled-cavity lasers
  •        Molecular Beam Epitaxy, e.g. homo- and heteroepitaxy-based thin film, nanowire
  •        Nanophotonics, e.g. Nanocavity LEDs, Lasers
  •        InP-based Photonic Integrated Circuits
  •        Silicon Photonics
  •       Quantum Photonics, e.g. single-photon emitters, single photon detectors

Schematic illustrating my future work which will be dedicated to interdisciplinary research relating to III-V compound semiconductor materials and devices that bridges engineering, optics, applied physics and nanoscience or nanotechnology.

Past Research Activities:

1. UCSB Research

My research at UCSB, CA, was primarily focused on the growth, design, fabrication and characterization of InP-based photonic integrated circuits, in particular, on-chip optical frequency synthesizer (OFS) using optical phase-locked loop (OPLL).

 

2. UCLA Research 

While at UCLA, My research was focused on

o  Patterned growth of GaAs films on silicon substrates : growth of high-quality and defect-free GaAs by molecular beam epitaxy on silicon dioxide patterned Silicon(111) substrates for building active optical devices including light emitting diodes, lasers and photodetectors on Si, making it a remarkable step towards an eventual demonstration of the microelectronic and optoelectronic devices on the same chip.

 

o   Van der Waals epitaxial growth of GaAs thin films on silicon using a two­dimensional layered material, graphene as a lattice-mismatch and thermal expansion coefficient mismatch-relieving buffer layer : a potential route towards heteroepitaxial integration of GaAs on silicon in the developing field of silicon photonics. On the way towards its realization, a deposition of high-quality GaAs films on graphene/silicon by molecular beam epitaxy and then a detailed material characterization are required.

o   Graphene as transparent electrode for GaAs-based vertical-cavity surface-emitting lasers: the graphene material-based electrode in VCSELs can bring three benefits: a reduced lateral resistance of the laser leading to an enhanced frequency modulation response and reducing the series resistance leading to an improved thermal characteristic.

 3. McGill Research 

While at McGill, my research was focused on the detailed optical and electrical characterization of III-nitride (AlGaInN) single nanowires. As it is known that 1D nanostructures, such as nanowires and nanorods, based on the III-nitride materials system have attracted attention as potential nanoscale building blocks in light emitting diodes (LEDs), lasers, sensors, photovoltaics, and high power and high speed electronics. Furthermore, I worked on the fabrication and optical performance of micro- and nanoscale quantum dot tube structures that are expected to emerge as novel building blocks for high-performing nanophotonic devices.

 

PhD research

My PhD thesis was focused on the development of novel electrically-pumped (EP) continuous-wave (CW) operating GaSb-based application-suited VCSELs in the wavelength range between 2.3 µm and 2.6 µm. In particular, much emphasis was laid on devices with record long emission wavelengths of 2.6 µm which exhibit single-mode operation with a reasonably wide mod-hop free tuning range. The design, fabrication and especially the characterization of such lasers were performed during the thesis. This thesis also presented some design principles for next generation high performance GaSb-VCSELs based on the device characterization results. The examination of the several individual components of the device and their successful implementation onto the device are also covered here.

Citation of my PhD thesis (book)

Shamsul Arafin, Electrically-Pumped GaSb-Based Vertical-Cavity Surface-Emitting Lasers, Selected Topics of Semiconductor Physics and Technology, vol. 138, Walter Schottky Institut, Garching, Germany, 2011. 136 pages. (ISBN 978-3-941650-38-1)

MSc research

My M.Sc. thesis was focused on the investigation into matrix addressable VCSEL array fabrication and the characterization afterwards. Recently this matrix addressable array has got great importance due to plenty of attractive applications like confocal microscopy, non-mechanical particle movement by optical tweezers, and video imaging where a large number of parallel optical sources with desired beam profile are needed. Matrix addressable VCSEL array can be the strong candidate to be implemented in these demanding applications since matrix addressing technique is capable of producing larger and denser 2-D array easily than independent. The entire work was performed on the sample designed for the standard wavelength regime around 850 nm, grown by solid source molecular beam epitaxy (MBE) on undoped GaAs substrate.

Citation of my MSc thesis

Shamsul Arafin, Invetigations into Matrix Addressable GaAs-VCSEL Arrays, M.Sc. Thesis, University Ulm, Germany, 2008. 126 pages.