Li Tian Chew completes Masters Degree Oral Defence

Congratulations to Li Tian Chew, who gave an excellent presentation and successfully defended her Master’s degree work on next generation memory technologies. The screenshot shows the moment that Li Tian was informed that she had passed. Under difficult circumstances amid the COVID19 outbreak, Li Tian had to present her work to the international thesis committee using video conferencing. Li Tian is among the pioneering batch of students on the SUTD-CGU Dual Masters Degree program in Nano Electronics Engineering and Design (NEED). She will be awarded two masters degree certificates (one from SUTD and one from Chang Gung University in Taiwan).

For more information about the NEED program and its scholarships, please see

6 papers accepted for presentation at IPS 2018

ACTAlab will be presenting the following papers at the Institute of Physics Singapore (IPS) meeting in March 2018:
  • Jitendra Kumar Behera, Xilin Zhou, Alok Ranjan, Robert Edwardsimpson:Optimisation of phase change van der Waals structures by statistical design of experiments
  • Li Tian Chew, Li Lu, Robert Simpson:Interfacial Damage in Phase Change Materials Tuned Optical Structures
  • Li Lu, Ramon Paniagua-Dominguez, Vytautas Valuckas, Arseniy I. Kuznetsov, Robert E. Simpson:Novel chalcogenide as a material platform for tunable nanoantenna arrays in the visible and near infrared spectrum
  • Jose Martinez, Weiling Dong, Robert Simpson:Optical response of chalcogenide phase-change materials
  • Jing Ning, Robert Simpson, Yee Kan Koh:Electrical, optical and thermal properties of Sb2Te3 and related materials.
  • Rob Simpson, Jitendra Behera, Janne Kallika, Xilin Zhou, “Active electronic and photonic materials by nanostructural design”

3 papers to be presented at MRS

ACTAlab has had the following three papers accepted for presentation at the MRS Spring meeting April 2018:

  • Metal Diffusion into Ge2Sb2Te5 and Implications for Photonics
  • Electric Field Effects in Chalcogenides
  • Novel chalcogenide as a material platform for tunable nanoantenna arrays in the visible and near infrared spectrum

Xilin Zhou wins prestigious prize

Congratulations to ACTAlab postdoc, Dr Xilin Zhou, for winning the best poster award at the Materials Research Society Spring Meeting, which was held in Phoenix USA April 2017. Xilin’s poster discusses the atomic transitions involved in Sb2Te-GeTe superlattices. In particular Xilin showed through a combination of experiments and simulations that the activation energy for disordering of the GeTe layers decreases as more atoms switch, and this leads to an avalanche switching effect.

There were more than 1500 posters presented at the conference, and only 9 were honored with a Best Poster Award. The photograph below shows Xilin with the meeting chairs.

Xilin Zhou photographed with the MRS Meeting Chairs at the poster session.


X. Zhou publishes new paper on tuning the properties of GeTe with Oxygen

Today, Xilin Zhou’s paper, which discusses how oxygen doping influences the the local structure of GeTe, has been published in ACS Applied Materials and Interfaces.

Interestingly when oxygen is added into GeTe, the energy required to switch the material in a phase change random access memory cell is lowered, yet counter intuitively the crystallization temperature is increased by O doping. Previously we showed that there is zero change in density for O concentrations of about 5 at.%. We believe that this allows the material to be switched with a lower enthalpy change, hence explaining the energy efficient  memory switching.

The paper is available here:



EPCOS 2016 – 3 papers accepted

Weiling Dong, Jitendra Behera, and Rob Simpson will present three papers at EPCOS 2016 in Cambridge, UK. The conference will be held in September 2016.

The papers are:

  • Wideband visible absorbers by Ge2Sb2Te5 and Al nanogratings, Weiling Dong, Yimei Qiu, Joel K.W. Yang, Robert E. Simpson, and Tun Cao
  • Laser switching of nanostructured phase change materials, Jitendra K. Behera, Xilin Zhou, and Robert E. Simpson
  • Genetic algorithm inspired design of Ge2Sb2Te5 structures, Robert E Simpson, Janne Kalikka, Jitendra K Behera, Giacomo Nannicini and Xilin Zhou 


See you in Cambridge!