InP Nanowire/Polymer Hybrid Photodiode

A novel design is presented for a nanowire/polymer hybrid photodiode. n-InP nanowires are grown directly onto an indium tin oxide (ITO) electrode to increase carrier collection efficiency and to eliminate the need for an expensive substrate. Experiments show that an ohmic contact is achieved between the nanowires and the ITO electrode. The nanowires are then enveloped by a high hole mobility conjugated polymer, poly(3-hexylthiophene). Compared to the control polymer-only device, the inclusion of InP nanowires increases the forward bias current conduction by 6−7 orders of magnitude. A high rectification ratio of 155 is achieved in these photodiodes along with a low ideality factor of 1.31. The hybrid device produces a photoresponse with a fill factor of 0.44, thus showing promise as an alternative to current polymer solar cell designs.