Giant enhancement in photoresponse via engineering of photo-induced charge (electron and hole) transfer in linear and non-linear devices

Publication date: Available online 31 January 2020Source: Sensors and Actuators A: PhysicalAuthor(s): G V Sai Manohar, S B Krupanidhi, K K NandaAbstractZinc oxide (ZnO) has been widely explored for UV detection despite its high exciton binding energy that can inhibit its photoresponse due to high probability of recombination. Here, we describe an approach that suppresses recombination and enhances the photoresponse via engineering of photo-induced charge transfer (PCT) in a linear MSM device Ag/ZnO/Ag and a non-linear p-Si/ZnO junction device. ZnO film when coated with carbon nanotubes (CNTs)/ nitrogen-doped CNTs (NCNTs) facilitates electron transfer and when coated with Poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) facilitates hole transfer, which inhibits recombination, increasing its photocurrent between 275 to 400 nm. This is one of the interesting approaches to enhance the photoresponse of a material. The extent of PCT depends on the amount of CNTs/NCNTs and PEDOT:PSS. Photocurrent was found to increase by ∼362-fold and ∼607-fold for 365 nm wavelength when NCNTs and NCNTs along with PEDOT:PSS were used as the recombination inhibitor on ZnO thin film, respectively. The responsivity was found to be 153 mA/W and 10.5 A/W, respectively for the coated Ag/ZnO/Ag linear and p-Si/ZnO non-linear device configurations, under 365 nm illumination. The enhancement is ∼15-fold for the non-linear devices. Overall, this work paves the way for an eleg...

Source: Sensors and Actuators A: Physical - February 1, 2020 Category: Physics Source Type: research