Very impressive, I really liked how low tech it all was (except for buying a high purity Si wafer but I can see why growing a crystal that size wasn't on the agenda). Nice to mention Jeri, that first 'cooking with Jeri' episode probably ranks as the all-time-high for makers in my book.
Same reaction to purportedly sub-$30/300degC homemade solar cells (BC lead poisoning) inclusive of equipment
https://youtu.be/3ghatCS0_HY
Anyway, very cool home project.