Founders Spotlight introduces the stories of Voima Ventures portfolio firm founders and CEOs. Last time at Founders Spotlight we talked with Ville Kolehmainen from Iiwari sharing his journey from a teacher to an indoor positioning company founder. This time we got together with Mikko Juntunen, the co-founder and CEO of ElFys.

ElFys disrupts the light sensing component market by providing a universal photodiode for all applications. They utilize advanced nanotechnology & atomic layer deposition techniques to produce light- and X-Ray detectors with superior sensitivity, accuracy, efficacy, and match with design.

What is your background and when did you first get familiar with photodetectors?

I was one of those kids that have been interested in math and science for as long as I can remember. I enthusiastically explained to my parents how many molecules there were in a single droplet of water – before elementary school. Crazy, I know… After high school I then naturally applied and got into Helsinki University of Technology to study engineering physics with the goal of becoming a theoretical physicist and to go to CERN to reveal the secrets of the world.

My goal of going to CERN was realized during summer 1990, and that is also the story of how my journey with detectors and semiconductors started. I was part of a team developing silicon strip detectors to precisely measure the paths of the elementary particles coming out of collisions in the Large Electron Positron collider of CERN. Having accomplished my goal of going to CERN I ended up deciding to say goodbye to my childhood theoretical physicist dreams, digging myself deep into experimental work, and finding my place with applications other than physics, and business.

After CERN, I joined Nokia Mobile Phones for a couple of years before jumping into Detection Technology, Inc that nowadays is a Nasdaq First North listed company. The company was a spin off from the very team I was part of at CERN. For almost a decade, I managed product development and did sales related to X-ray imaging, including computed tomography. It was a nice fit for me, requiring understanding of ionizing radiation, interaction of radiation with matter, electronics manufacturing and of course – photodiodes – to satisfy the needs of actual people in the actual marketplace.

How did you meet your co-founders and was it an easy decision to start ElFys together?

I met Dr. Antti Haarahiltunen, one of the founders and CTO of Elfys, and professor Hele Savin of Electron Physics Group of Aalto University, one of the founders and presently member of the Board of Elfys, already during my time at Detection Technology, Inc. Closer cooperation between us started after I completed my doctoral thesis about tileable photodetectors (as a rather strange hobby) in 2013, almost 20 years after having left CERN.

In 2013 I joined Hele’s team at Aalto University and that’s where I got infected by their excellent developments in Black Silicon to enhance the energy efficiency of solar cells. As dark as it sounds, I fell in love with blackness. With the group we did some remarkable research. With a few miracles and some magic touch of many excellent engineers and scientists, we ended up having made a handful of photodiodes that looked a little suspicious, but proved to be of amazing performance.

After running an R2B project (ex TUTL) with Business Finland (ex Tekes) funding in the university, the team working with the subject decided that there is enough potential to go for it, and we did. For me, this was quite an easy decision. I really felt that we had accomplished something very extraordinary, and my personal situation was suitable for such a major move and risk taking, so we took on the challenge.

ElFys team in November 2019.

You founded ElFys back in 2017. What have been some of the best moments during your journey so far?

Easily the best moments in our ElFys endeavour have been related to customers telling how our technology provides them value building trust and potential for our future. And I also have to mention the  victorious moments with the team when we received our first major purchase orders from customers in the early days of ElFys.

On a more personal note, as a physicist, I’m used to relying on the laws of nature. And with those laws, things can be predicted that are sometimes quite amazing. Therefore, our inventive black silicon induced junction photodiode sort of inevitably must provide close to 100% quantum efficiency. Still it was a powerful feeling to actually see the first results proving it, and being able to repeat it over and over again. 

What about some of the hardest moments?

This is a hard question to answer and perhaps the hardest moments are the ones you cannot share. But one thing that I’ve lately realized is that when you have been part of many projects and endeavours, you grow more resistant to the struggles. You learn to navigate your way around them and keep the goal clear in your mind even with a bit of turbulence.

In the beginning, I would say that the biggest challenges were around spinning out and having to figure out how to deal with everything on our own while also keeping the research and development going. Luckily, I never needed to be alone in this, being able to rely on many people along the path, including obviously those of the founding team.

What are the most exciting milestones you are looking to achieve in 2021 and beyond?

This year, we are looking forward to entering into our first continuous volume delivery agreements. Which is a big step in the right direction and we have been waiting to make. Another major step to be taken in 2021-2022 is to expand our manufacturing capacity to be able to meet the demand of photodiode components of the consumer wearable device market. Which means more than 10-folding our production capacity. We cannot wait for more people to begin to benefit from the power of our product.

Read more about ElFys at