In Episode 28 of ALD Stories, Tyler is joined by Aalto University’s Hele Savin. Hele is a professor in the department of Electronics and Nanoengineering where she uses ALD to engineer photovoltaics and semiconductor devices. In 2017, Hele was awarded the women’s innovation prize from the Finnish parliament after fabricating a black silicon solar cell with a record-breaking 22.1% efficiency and currently uses ALD to create induced junction photodiodes with over 100% external quantum efficiency.  

Hele and Tyler discuss how she was first exposed to ALD by Beneq, a mindset that using ALD was dirty, and how mind-blowing early ALD passivation results were. We also talk about why ALD oxides are better than thermal SiO2, the theoretical implications of breaking 100% EQE, and upcoming work in up conversion in her lab. 

In this episode: 

00:00 Intro 

07:45 First experience with ALD 

16:37 Passivation of Black Si Solar cells 

29:52 ALD for Induced Junction Diodes 

39:06 Theoretical Implications of High EQE 

47:35 Future Up Conversion work