Fabrication and characterization of transparent MEH-PPV/n-GaN (0 0 0 1) heterojunction devices

n-GaN/MEH-PPV thin film heterojunction diode was fabricated by depositing MEH-PPV thin film using spin-coating process on n-GaN (0 0 0 1). The junction properties were evaluated by measuring I–V characteristics. I–V characteristics exhibited well defined rectifying behavior with a barrier height of 0.89 eV and ideality factor of 1.7. The optical band gap of the MEH-PPV film using optical absorption method was found to be 2.2 eV and the fundamental absorption edge in the film is formed by the direct allowed transitions. At higher electric fields, the conductivity mechanism of the film shows a trap charge limited current mechanism. The obtained results indicate that the electronic parameters of the heterojunction diode are affected by properties of MEH-PPV organic film.

► I have fabricated MEH-PPV/n-GaN/Au heterostructure by spin coating.
► The current–voltage (I–V) characteristic of MEH-PPV/n-GaN shows diode-like behavior.
► MEH-PPV interfacial layer affects electrical parameters of the Au/n-GaN structures.
► I–V measurements suggest that the charge transport mechanism is controlled by TCLC.