# How to find out which organic molecules would be good electron acceptors/donors on a GaAs semiconductor surface [closed]

I'm a physicist in way over my head. I have a list of organic molecules to investigate, all common aldehydes and amines. My supervisor wishes to know which of these molecules would be good electron donors and which would be good electron acceptors.

The idea is to use some of these molecules to dope some GaAs nanowires, in order to be able to tweak the Fermi level at the edge states. What are the properties I should be looking for? I am guessing that compounds with very electronegative elemental constituents will be good electron acceptors and vice versa for those with electropositive constituents but other than that I am unsure where to find the information I need. Could anybody point me in a helpful direction?

Some one else mentioned electron affinities and ionisation potential but I have no idea where to look for these things in the literature. My chemical understanding is limited to what I know about physics and advanced high school chemistry.

• Look for the literature entering "organic donor and acceptors" "P and N-type organic semiconductors" for instance. If both you and your supervisor are new to these things, "organic electronics" is somehow an established field of research. You will find plenty of reviews. As it is quite intrinsic to their nature, carbon compounds tends to be of P type. Triphenylamibes and carbazoles are known since long time to be holes transporting materials. Conjugated polymers are relatively newer. . Although purely carbon based, fullerenes are the most outstanding molecules on the N side. Just start search. – Alchimista Aug 20 '17 at 14:50
• I realise you cannot choose the molecule. :( – Alchimista Aug 20 '17 at 14:51
• You probably need to look for tables of redox potentials such as in the CRC handbook of Chemistry & Physics. The free energy of the reaction is $\Delta G = E_{donor}-E_{acceptor}$. So GaAs could be donor or acceptor. Look for values, say, for a known donor and compare other molecules with this. Also look at Marcus theory of electron transfer as too large a $-\Delta G$ can lead to slow electron transfer reaction, as a rule of thumb -$1$eV is ok – porphyrin Aug 21 '17 at 15:19