In this work, a significant visible-light photovoltaic effect is obtained under the influence of a built-in electric field in BiFeO3 thin films. The photocurrent density, open-circuit voltage, and ...

Photovoltaic Effect Induced by Self-Polarization in BiFeO3 Films

All solution processed flexible p-NiO/n-CdS rectifying junction: Applications towards broadband photodetector and human breath monitoring

Two-dimensional perovskite Sr2Nb3O10 nanosheets meet CuZnS film: facile fabrications and applications for high-performance self-powered UV photodetectors

In the majority of the chemical deposition techniques used for doping thin films, dopant cations are usually added to the reaction simultaneously with the host cations, or even after the formation of the host matrix. This approach reduces the dopant efficiency and reproducibility of dopant-related properties. In the present work, the nucleation-doping strategy usually used for colloidal nanocrystals is extended into the chemical bath deposition technique to prepare cobalt-doped CdS nanostructured thin films. The Co:CdS thin films showed %2.5 doping yield with a root-mean-square roughness below 22 nm and absorption edge below 510 nm. The PL emission spectra of the films revealed two distinct peaks at 490 and 530 nm, attributed to the recombination processes through excitonic states and impurity levels, respectively. Almost all the experimental variables were optimized to reach a partially single-emission peak at 530 nm, which can prove the successful incorporation of Co ions into CdS nanostructures.

Improved chemical deposition of cobalt-doped CdS nanostructured thin films via nucleation-doping strategy: Surface and optical properties

We report on the optoelectronic characteristics of p-NiO/n-Si heterojunction photodiode for broadband photodetection, fabricated by depositing a p-type NiO thin film onto a commercial n-type silicon substrate using pulsed laser deposition (PLD) technique. The structural properties of the PLD-grown p-NiO material were analysed by means of x-ray diffraction and x-ray photoelectron spectroscopy, confirming its crystalline nature and revealing the presence of Ni vacancies, respectively. Hall measurements confirmed the p-type semiconducting nature of the NiO thin film having a carrier concentration of 8.4 × 1016 cm−3. The current–voltage (I–V) characteristics of the p-NiO/n-Si heterojunction photodevice were investigated under different wavelengths ranging from UV to NIR. The self-bias properties under different illuminations of light were also explored systematically. Under self-bias condition, the photodiode exhibits excellent responsivities of 12.5 mA W−1, 24.6 mA W−1 and 30.8 mA W−1 with illumination under 365 nm, 485 nm, and 850 nm light, respectively. In addition, the time dependency of the photoresponse of the fabricated photodevice has also been investigated and discussed thoroughly.

Laser ablation fabrication of a p-NiO/n-Si heterojunction for broadband and self-powered UV–Visible–NIR photodetection

Solution-processed photodetectors have emerged as the next generation of sensing technology owing to their ease of integration with electron devices and of tuning photodetector performance. Currently, novel self-powered photodetectors without an external power source, for use in sensing, imaging and communication, are in high demand. Herein, we successfully developed a self-powered photodetector based on a novel solution-processed p-NiO/n-CdS:Al heterojunction, which shows an excellent current rectification characteristic ratio of up to three orders in the dark and distinctive photovoltaic behavior under light illumination. The complete solution synthesis route followed the development of CdS:Al thin films on ITO substrates by chemical bath deposition and NiO thin films by the sol-gel route. Optical absorption data revealed that NiO is more active in the UV region and CdS:Al has a majority of absorption in the visible region; so, upon light illumination, the effective separation of photogenerated carriers produces fast photodetection in the UV-visible region. The photoresponsivity values of the fabricated device were calculated to be 55 mA W-1 and 30 mA W-1 for UV and visible illumination, respectively. Also, the device has a fast rise and decay photoresponse speed at zero bias voltage, due to the self-driven photovoltaic effect which makes this heterojunction a self-powered device. This complete solution and new method of fabrication make it possible to combine different materials and flexible substrates, enhancing its potential applications in photodetectors, optoelectronic devices and sensors.

Rafael Ramirez Bon

Papers

Self-powered broadband photodetector based on a solution-processed p-NiO/n-CdS:Al heterojunction.