Effects of interfacial oxide layer in P3HT/n-Si organic/inorganic heterojunction diodes on their carrier transport properties

Current density–voltage (J–V) characteristics of poly(3-hexylthiophene) (P3HT)/n-silicon heterojunctions are investigated to improve the electrical characteristics of organic/inorganic heterojunction diodes. The diodes are fabricated by spin coating P3HT with SiC or post-HF treatment. These treatments are effective in suppressing the interfacial oxide between the P3HT and Si layers, where the forward current density is improved effectively. The thickness of the interfacial oxide layer correlates with improvements of not only the forward-bias current but also the ideality factor. The interfacial oxide layer effect on the carrier transport properties is discussed using a metal–insulator–semiconductor junction model.

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► J–V characteristics of poly(3-hexylthiophene)/n-Si heterojunction are investigated.
► SiC and post-HF acid treatments on Si are effective in enhancing the forward current density.
► Effects of the interfacial oxide layer on the carrier transport are discussed.