(A*STAR) Bayesian driven yield optimization for direct-bandgap group IV lasing using high-throughput optoelectronic measurements

Direct laser emission from silicon has long been a dream within the on-chip photonics community. While many approaches have been attempted, the lack of a direct bandgap in silicon prohibits efficient radiative recombination. In 2020, Bakkers and colleagues reported that hexagonal structured (wurtzite) germanium could be grown using a wurtzite GaAs nanowire template, opening a new front (Nature 508, 205, 2020). However, their approach – using gold-seeded MBE growth – is incompatible with CMOS processes, and the production of such structures without gold has proven to be extremely low yield due primarily to the large parameter space in the growth process.

 An established collaboration between Manchester (UoM) and University College London (UCL) has led to initial gold-free growths of hexagonal materials, with UoM providing high-throughput automated single structure spectroscopy to identify candidate elements. However, photocurrent measurements are often far more sensitive in the infrared and are better probe of optical absorption (and hence band structure) of novel materials.

 In this project, students will make use of the high-throughput electrical capabilities at A*STAR to tackle this challenge. Specifically, building upon the Accelerated Materials Development Program led from IMRE, rapid electrical and opto-electrical testing has been developed. This is done via a computer-vision integrated modular stage platform. 

 High quality samples with known low-temperature photoluminescence properties will be prepared and fabricated into high-throughput single wire photodetector devices to be tested at A*STAR. The properties will be measured (absorption, photocurrent etc) and correlated with photoluminescence and imaging properties to create low-cost proxy measurements for material quality. A Latin Hypercube Sampling coupled with Bayesian optimization strategy will be developed to target high-yield growth, with a feedback loop between growth, ultra-high throughput imaging and spectroscopy and targeted electrical measurements and analysis.

 The aim of the project is to rapidly identify a parameter space for growth of high-yield direct bandgap silicon as a revolutionary CMOS-compatible on-chip coherent light source.

Entry Requirements:

Applicants must have obtained or be about to obtain a First or Upper Second class UK honours degree, or the equivalent qualifications gained outside the UK, in a related subject area.

Many of our students have also undertaken a master's degree, although this is not compulsory.

 International applicant eligibility requirements: Some restrictions apply to applicants from certain Asian countries. In general, students from Europe, the Americas, Africa, Australia, New Zealand, Korea and Japan are eligible to apply for the programme. Unfortunately, we cannot accept applications from south-east Asian countries such as Singapore, China and Malaysia.

International applicants must ensure they meet the academic eligibility criteria (including English language) as outlined before contacting potential supervisors to express an interest in their project.

How to Apply

To be considered for this project you MUST submit a formal online application form - full details on how to apply can be found on the A*STAR PhD website https://www.bmh.manchester.ac.uk/study/research/astar/

Equality, Diversity and Inclusion

Equality, diversity and inclusion is fundamental to the success of The University of Manchester, and is at the heart of all of our activities. The full Equality, diversity and inclusion statement can be found on the website https://www.bmh.manchester.ac.uk/study/research/apply/equality-diversity-inclusion/