NORWEGIAN UNIVERSITY OF SCIENCE & TECHNOLOGY - NTNU

PhD Positions on Growth, Fabrication and Characterization of Semiconductor

Location
Trondheim, Norway
Posted
18 Mar 2021
End of advertisement period
16 Apr 2021
Ref
2021/15784
Contract Type
Temporary
Hours
Full Time

About the position

Two PhD-positions are available at the Department of Electronic Systems (IES) at the Norwegian University of Science and Technology (NTNU). The positions will be in the “III-V semiconductor nano-device” group at IES.

The “III-V semiconductor nano-device” group at IES focuses on growth, characterization and processing of hybrid III-V semiconductor nanowire/graphene structures for use in various optoelectronic applications including solar cells, LEDs and lasers. The III-V nanowires are grown on graphene substrates in the molecular beam epitaxy (MBE) lab at the department (Prof. Fimland). A YouTube animation video explaining this technology can be found here: (http://www.youtube.com/watch?v=3wLOXHRVVwQ). Optoelectronic characterization of individual nanostructures and devices is done using techniques such as low temperature micro-photoluminescence, photocurrent and electroluminescence, using a Nanophotonics lab at the department (Prof. Weman). For fabrication of the nano-devices, the NTNU NanoLab cleanroom facility is used. 

The two PhD positions available in this announcement are connected to the project “Ultraviolet nanowire/graphene laser” (UV-Nanolaser) funded jointly by the NANO2021 program of the Research Council of Norway and NTNU. The objective of the UV-Nanolaser project is to develop electrically injected semiconductor laser diodes based on positioned AlGaN nanowires grown by MBE on a graphene-based nanohole-mask. The final laser device will incorporate optical feedback based on a combination of Photonic Crystal (PC) effects and Distributed Bragg Reflectors (DBR) in order to develop an electrically semiconductor laser operating in the germicidal ultraviolet UVC spectral range (<280 nm). Such lasers are today in high demand for e.g. water, air and surfaces disinfection and sterilization of bacteria and viruses and in many applications in medicine, in particular in ophthalmology and dermatology.

The project involves collaboration with the spin-off company CrayoNano as well as international academic partners.

The PhD positions are for 4 years (with 25 % duty work assignments at IES). Starting dates for the positions are August 2021.

Academic supervisors for the positions will be Professor Helge Weman and Professor Bjørn-Ove Fimland. For employee matters you will report to the Head of IES.

Duties of the position

The successful candidates will work on either of the two following topics.

1. Growth and structural characterization of positioned AlGaN nanowires on graphene hole masks.

The PhD student on this topic will work on the MBE growth and structural characterization of the positioned AlGaN nanowires as well as on the hole mask fabrication. Graphene will be used as a substrate and hole mask for the AlGaN nanowire growth as well as a transparent electrode for the subsequently processed UV nanolasers. The graphene mask, with a periodic hexagonal hole pattern, will be fabricated with electron beam lithography (EBL). Selective-area growth of vertical AlGaN nanowires on the graphene hole mask will then be performed, whereby the nanowire diameter, position and length will be adjusted to tune the optical cavity parameters and obtain a photonic band gap at the lasing wavelength. The PhD student will start the project with a study of positioned GaN nanowires before growing more advanced hetero-structured p-i-n GaN/AlGaN nanowires including quantum wells and electron blocking layers. Different characterization techniques (I-V, SEM, TEM, XRD, and micro-Raman spectroscopy) will be employed to optimize growth selectivity, morphology, doping and the hetero-structuring of the grown GaN/AlGaN nanowires on the graphene hole-mask. The positioned AlGaN nanowires on graphene will be either grown directly or delaminated and transferred onto high-reflective AlGaN or oxide DBR substrates (fabricated by collaboration partners) to be used as the bottom cavity mirror in the UV nanolaser. A newly refurbished III-nitride plasma-assisted MBE machine will be dedicated for the AlGaN NW growth in the project.

2. Optical and electrical characterization and device fabrication of AlGaN nanowire/graphene lasers

The PhD student on this topic will work on optical and electrical characterization as well as device fabrication of the UV nanolasers. Initially, before device fabrication of electrically injected UV nanolasers has been achieved, a major part of the studies will be on the optical characterization and optical pumping-induced lasing of the positioned AlGaN nanowires grown on graphene. The optical studies will be performed mainly with micro-photoluminescence spectroscopy, using the newly UV-upgraded Nanophotonics lab at IES. The apparatus allows for room and low (10 K) temperature measurements including polarisation- and time-resolved micro-PL of single nanowires as well as on nanowire arrays.  For the UV nanolaser device fabrication, optimised AlGaN nanowire arrays grown on DBR will be processed with photolithography to fabricate electrical contacts to both the graphene bottom transparent electrode on the DBR mirror and for the top electrode of the AlGaN nanowires. The device fabrication will be performed using different tools available in NTNU NanoLab cleanroom facility. All fabricated devices will be examined in a probe station setup equipped with spectrograph and charge-coupled device to obtain electroluminescence spectra. Additionally, the total emitted power will be measured with a dedicated setup to measure the wall-plug-efficiency of the UV nanolasers. The µ-PL experimental setup is also fully suited for optical characterisation of the laser diodes.

Common duties in both PhD positions:

  • collaboration with the other internal and external project members of the UV nanolaser project including PhD students, postdocs, researchers and engineers 
  • writing journal articles and dissemination of results at international conferences and workshops

Required selection criteria

The PhD-position's main objective is to qualify for work in research positions. The qualification requirement is that you have completed a master’s degree or second degree (equivalent to 120 credits) with a strong academic background in electrical engineering, nanotechnology, materials science or physics with a specialization within e.g., physical electronics, semiconductor materials, or materials physics or equivalent education with a grade of B or better in terms of NTNU’s grading scale. If you do not have letter grades from previous studies, you must have an equally good academic foundation. If you are unable to meet these criteria you may be considered only if you can document that you are particularly suitable for education leading to a PhD degree.

Applicants are required to justify their candidateship by explicitly explaining their personal motivation and academic aptitude for pursuing a doctoral degree within this research field. Applicants that expect to complete their master’s degree studies at the latest by July 31, 2021 can apply. Academic results, publications, relevant specialization, work or research experience, personal qualifications, and motivation will be considered when evaluating the applicants. 

Excellent English skills, written and spoken, are required. Applicants from non-European countries where English is not the official language must present an official language test report. The following tests can be used as such documentation: TOEFL, IELTS or Cambridge Certificate in Advanced English (CAE) or Cambridge Certificate of Proficiency in English (CPE). Minimum scores are:

  • TOEFL: 600 (paper-based test), 92 (Internet-based test)
  • IELTS: 6.5, with no section lower than 5.5 (only Academic IELTS test accepted)
  • CAE/CPE: grade B or A.

Preferred selection criteria

  • candidates with documented strong relevant experimental and theoretical skills 

The appointment is made in accordance with the regulations in force concerning State Employees and Civil Servants and national guidelines for appointment as PhD, post doctor and research assistant.

Personal characteristics

  • strong self-motivation and curiosity driven
  • ability to work independently and the ability to work as part of a team.
  •  excellent written and verbal communication, including presentation skills
  •  challenges the status quo and promotes new initiatives. 
  • ability to think logically, create solutions and make informed decisions 

We offer

Salary and conditions

PhD candidates are remunerated in code 1017, and are normally remunerated at gross from NOK 482 200 per annum before tax, depending on qualifications and seniority. From the salary, 2% is deducted as a contribution to the Norwegian Public Service Pension Fund.

The period of employment is 4 years with 25% work duty assignments for the Department of Electronic Systems. 

Appointment to a PhD position requires that you are admitted to the PhD programme in Electronics and Telecommunications within three months of employment, and that you participate in an organized PhD programme during the employment period. 

The engagement is to be made in accordance with the regulations in force concerning State Employees and Civil Servants, and the acts relating to Control of the Export of Strategic Goods, Services and Technology. Candidates who by assessment of the application and attachment are seen to conflict with the criteria in the latter law will be prohibited from recruitment to NTNU. After the appointment you must assume that there may be changes in the area of work.

About the application

The application and supporting documentation to be used as the basis for the assessment must be in English.

Publications and other scientific work must follow the application. Please note that applications are only evaluated based on the information available on the application deadline. You should ensure that your application shows clearly how your skills and experience meet the criteria which are set out above. 

The application must include:

  • a cover letter including an explanation of how your research interests and background would fit the position
  •  CV, certificates and diplomas
  • a one page “qualifications” document explicitly detailing how you meet each of the required and some (or all) of the desired qualifications listed above. An application missing this document may be considered incomplete by the selection committee.
  • academic works - published or unpublished - that you would like to be considered in the assessment
  • name and address of two referees, and relation to candidate

Joint works will be considered. If it is difficult to identify your contribution to joint works, you must attach a brief description of your participation.

In the evaluation of which candidate is best qualified, emphasis will be placed on education, experience and personal suitability.

NTNU is committed to following evaluation criteria for research quality according to The San Francisco Declaration on Research Assessment - DORA.

General information

Working at NTNU

A good work environment is characterized by diversity. We encourage qualified candidates to apply, regardless of their gender, functional capacity or cultural background. 

The city of Trondheim is a modern European city with a rich cultural scene. Trondheim is the innovation capital of Norway with a population of 200,000. The Norwegian welfare state, including healthcare, schools, kindergartens and overall equality, is probably the best of its kind in the world. Professional subsidized day-care for children is easily available. Furthermore, Trondheim offers great opportunities for education (including international schools) and possibilities to enjoy nature, culture and family life and has low crime rates and clean air quality.

As an employee at NTNU, you must at all times adhere to the changes that the development in the subject entails and the organizational changes that are adopted.

In accordance with the The Public Information Act (Offentleglova), your name, age, position and municipality may be made public even if you have requested not to have your name entered on the list of applicants.

If you have any questions about the position, please contact Professor Helge Weman, helge.weman@ntnu.no, or Professor Bjørn-Ove Fimland, bjorn.fimland@ntnu.no

If you have any questions about the recruitment process, please contact Randi Hostad, e-mail: randi.hostad@ntnu.no

Please submit your application electronically via jobbnorge.no with your CV, diplomas and certificates. Applications submitted elsewhere will not be considered. Diploma Supplement is required to attach for European Master Diplomas outside Norway. Chinese applicants are required to provide confirmation of Master Diploma from China Credentials Verification (CHSI).

If you are invited for interview you must include certified copies of transcripts and reference letters. Please refer to the application number 2021/15784 when applying. 

Application deadline: 16.04.2021

NTNU - knowledge for a better world

The Norwegian University of Science and Technology (NTNU) creates knowledge for a better world and solutions that can change everyday life.

Department of Electronic Systems

The digitalization of Norway is impossible without electronic systems. We are Norway’s leading academic environment in this field, and contribute with our expertise in areas ranging from nanoelectronics, phototonics, signal processing, radio technology and acoustics to satellite technology and autonomous systems. Knowledge of electronic systems is also vital for addressing important challenges in transport, energy, the environment, and health. The Department of Electronic Systems is one of seven departments in the Faculty of Information Technology and Electrical Engineering .

Deadline 16th April 2021
Employer NTNU - Norwegian University of Science and Technology
Municipality Trondheim
Scope Fulltime (2 jobs)
Duration Temporary
Place of service Campus Gløshaugen

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