Fully Solution-Processed ZnO Nanorod Array/PEDOT:PSS Heterojunction Photodetector for Ultraviolet Light
Chandan Kumar, Ajinkya Palwe, Sweta Rani, Sumit Saxena, Shobha Shukla
Abstract
This letter reports an inorganic/organic heterojunction photodetector using n-type zinc oxide nanorod array (NRA) and p-type poly3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS). ZnO NRA is grown hydrothermally on the ZnO quantum dots (QDs) seed layer deposited on indium tin oxide (ITO) substrate. Further, ZnO NRA is treated with ZnO QDs to get rid of pinholes and PEDOT:PSS is spin-coated over ZnO NRA for the formation of heterojunction. The fully solution-processed ZnO NRA/PEDOT:PSS heterojunction photodetector has a top electrode of printable carbon paste. The ultraviolet (UV) photodetector has shown a maximum responsivity of 9.2 A/W and detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.3\times 10^{{12}}$ </tex-math></inline-formula> cmHz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {1/2}}\text{W}^{-{1}}$ </tex-math></inline-formula> under the UV light illumination of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\boldsymbol {\sim }364$ </tex-math></inline-formula> nm wavelength with a power density of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$102.3~ \boldsymbol {\mu }$ </tex-math></inline-formula> Wcm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> . Additionally, UV photodetector is highly spectrum selective with promising SNR and faster response.