Three-Dimensional Arrays of Lead Halide Perovskite Nanowire Based Image Sensors
Authors: Fan Zhiyong , Gu Leilei , Tavakoli Mohammadmahdi , Zhang Daquan 
Published: February 2020

Lead halide perovskite materials are emerging as highly promising materials for high performance optoelectronic devices thus triggered broad attention globally. In this work, we report for the first time a chemical vapor deposition (CVD) process to grow ordered three-dimensional (3-D) MAPbI3 NW arrays in nanoengineering templates. This unique CVD process utilizes Pb metal nanoclusters at the bottom of vertical nanochannels to initiate high quality MAPbI3 NW growth. As the nanochannels have largely controllable geometrical factors, namely, periodicity, diameter and depth, NW geometry can also be precisely nanoengineered. As the result, the ordered 3-D NW arrays can achieve ultra-high NW density in the range of 4×108/cm2~109/cm2 at a sizable scale of ~9 cm2. The 3-D NW arrays are conspicuously promising for 3-D integrated nano-electronics/optoelectronics. To further demonstrate the technological potency of the perovskite NW arrays, they have been fabricated into proof-of-concept image sensors. Each image sensor consists of 1,024 photodiode pixels made of vertical perovskite NWs, and the imaging functionality has been verified by recognizing various optical patterns projected on the sensor. It was found that the NW sensors can respond to dynamic optical input with reasonable speed, thus video capturing function of the NW image sensor was also successfully demonstrated. As the diameter of each NW can be as small as hundreds of nanometers and each NW can serve as one sensor pixel, this unique image sensor design can potentially lead to extremely high resolution approaching optical diffraction limit. In addition, fabrication and characterization of flexible image sensors have also been demonstrated in this work. The flexible optical sensor arrays can find broad applications for wearable electronics, electronic eyes, multifunctional robotic and artificial skins, etc. Lead halide perovskite materials are emerging as highly promising materials for high performance optoelectronic devices thus triggered broad attention globally. In this work, we report for the first time a chemical vapor deposition (CVD) process to grow ordered three-dimensional (3-D) MAPbI3 NW arrays in nanoengineering templates. This unique CVD process utilizes Pb metal nanoclusters at the bottom of vertical nanochannels to initiate high quality MAPbI3 NW growth. As the nanochannels have largely controllable geometrical factors, namely, periodicity, diameter and depth, NW geometry can also be precisely nanoengineered. As the result, the ordered 3-D NW arrays can achieve ultra-high NW density in the range of 4×108/cm2~109/cm2 at a sizable scale of ~9 cm2. The 3-D NW arrays are conspicuously promising for 3-D integrated nano-electronics/optoelectronics. To further demonstrate the technological potency of the perovskite NW arrays, they have been fabricated into proof-of-concept image sensors. Each image sensor consists of 1,024 photodiode pixels made of vertical perovskite NWs, and the imaging functionality has been verified by recognizing various optical patterns projected on the sensor. It was found that the NW sensors can respond to dynamic optical input with reasonable speed, thus video capturing function of the NW image sensor was also successfully demonstrated. As the diameter of each NW can be as small as hundreds of nanometers and each NW can serve as one sensor pixel, this unique image sensor design can potentially lead to extremely high resolution approaching optical diffraction limit. In addition, fabrication and characterization of flexible image sensors have also been demonstrated in this work. The flexible optical sensor arrays can find broad applications for wearable electronics, electronic eyes, multifunctional robotic and artificial skins,etc.