Organic-on-GaAs contact barrier diodes

Publisher Website
Google Scholar
Abstract
Thin films of the organic compound 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) were deposited on n- and p-type GaAs substrates, and were found to form high contact barriers. Barrier energies of 0.64 eV on n-type substrates and 0.75 eV on p-type material yielded organic-on-inorganic (OI) contact barrier diodes characterized by exponentially increasing forward current with voltage, and a reverse dark current leakage limited by generation and recombination of carriers in the GaAs bulk. The Fermi level does not appear to be pinned at the OI interface, contrary to what is commonly observed in metal/GaAs Schottky barrier diodes. In addition, we have made OI contact barriers using N,N′-dimethyl 3,4,9,10-perylenetetracarboxylic diimide (DIME-PTCDI) deposited on n- and p-type GaAs. These devices have contact barriers of 0.85 eV for substrates of either majority-carrier-type. The n values obtained from the forward biased characteristics of the GaAs/DIME-PTCDI structures are n=1.19, and are the lowest obtained to date for OI devices.