Ahmed Abubakar Alao

PhD Student Sep 2017 - Sep 2022

tainan

Within my five years and a month experience as a research assistant at the NEXT-G Lab in NCKU materials science and engineering department, I have worked on numerous projects, and one of such was on Silicon Carbide (SiC) single crystal growth in the Physical Vapor Transport (PVT) process. My research goal was to find a way of stabilizing silicon carbide polymorphs (4H-SiC and 6H-SiC), and also, improve the boule (crystal) purity and quality. This is achieved by understanding the process parameters responsible for polymorph stability, the kinetics and thermodynamics of the reactions in the process.

Silicon carbide synthesis faces polymorph/polytype stability challenges, as two of the most common polymorph, 4H-SiC and 6H-SiC, which are more suitable for electronics application have closely related formation energies. Therefore, the reason we improved one of the most important process parameters responsible for polymorph stability which is the Si/C ratio. Other process operating parameters responsible are growth temperature, substrate orientation type, dopant and insitu etch. This silicon carbide project, has led to two SCI publications and a manuscript presently undergoing review for submission in Carbon Journal.

Furnace geometry design, mass transport and thermal field of the growth furnace was another important area I have investigated, since some of the process parameters of the crystal growth process cannot be determined experimentally. Aside from this project, I have worked on other exciting projects such as development of novel high entropy alloys and calculation of their electrical conductivity and relaxation time used as coatings on substrates for communication device applications. Another high entropy alloy developed, was for application as a thin nanocoating on multimeter tips, for the tip life span enhancement while testing semiconductor test boards. This project has led to so many manuscripts, which are currently undergoing review for publication and a patent which is already granted/published. And also, i have worked on fuel cell electrode design for energy generation.

Master Student Mar 2014 - Mar 2016

University of Ibadan

During my two years research as a research assistant at the department of mechanical engineering, university of ibadan, I have worked on Forced convection of nanofluids in external and internal flow regimes, in different media. The project aim, was to find the right nanofluid to be used as industrial coolant, and also, study the fluid behavior/characteristics in the flow regimes. Aside from this exciting and promising project, I have worked on a group project, aimed at determining the distribution of temperature (heat transfer) on an industrial hollow square duct subjected to different external and internal temperatures. This investigation was carried out using finite difference approach and MATLAB.

National Cheng Kung University 2017 - 2022

Field of study: Materials science and engineering
Degree: PhD

As a research assistant at the Materials Science and Engineering department, NEXT-G Lab, I have worked on numerous projects, which include project on silicon carbide (SiC) PVT process improvement, especially the stability of polymorph since SiC synthesis process faces polytype stability problems due to the closeness of the formation energies of the commonly found polytypes and thermal field, mass transport and crystal growth simulation. Aside from this fascinating and interesting field, I have worked on design of high entropy alloy series, calculation of their electrical conductivities and relaxation time for application in substrate coatings for communication devices. And also, fuel cells electrode design as catalyst. Below are some excerpt describing parts of the silicon carbide project and the high entropy alloy, respectively.

SiC is a compound semiconductor synthesize via PVT process, due to its lack of molten state in the ambient pressure within a reasonable temperature. During the process, it is difficult to experimentally measure the substrate temperature which is used as seed for the crystal growth, even with laser. Therefore, the need to use simulation tools such as COMSOL to determine the thermal field.

Conventional microwave ceramic communication devices face challenges of their metal electrodes diffusing and shifting of resonance frequency of the electrodes. Therefore, the need to replace the conventional ceramic substrate in the device or provide a thin nano-coating with exceptional mechanical properties such as sluggish diffusion that prevents the stated problem. We developed the former.