Question: how do you grow carpets of zinc oxide??

Kieren Bradley answered on 18 Mar 2014:

First I get some glass and use a sharp point to score it and then snap it to the correct size (1cm x 2cm), next I put droplets of zinc acetate (a chemical with zinc in it which smells like vinegar) disolved in ethanol (alcohol) onto the glass. Once a number of drops have gone on I then heat it up to 350 C (hotter than your oven at home) and it turns into a flat layer on zinc oxide. The sample goes Into a bath of zinc nitrate (another chemical with zinc in, but doesn’t really smell) and hexamethyltetraamonium (HMT: a useful chemical but smells like rotten fish!) in water. when the bath is heated up the zinc in the water attaches to the zinc oxide already on the glass. The HMT then adds oxygen from water molecules onto the zinc to make zinc oxide. The top side of the zinc oxide doesn’t like water but the sides do so it prefers to grow with really tall sides and really small tops which is why it grows into lots of pillars like a carpet or forest. Have a look at my profile to see a nice picture of them from above.