As one of the cornerstones of photoelectric detection system, ultraviolet (UV) detector has the ability to convert UV signal into electrical signal, which is widely used in optical communication, biomedicine, and other fields. NiO has a strong absorption of UV light due to its wide band gap of 3.4 to 4.1eV. In addition, NiO exhibits a p-type conduction at room temperature. Thus, it is often used to form a pn junction in combination with a n-type semiconductor for photodetection. Si has the unique advantages of being integrated and compatible with CMOS processes. By constructing the NiO/n-Si heterojunction, the advantages of Si and NiO can be combined to prepare high performance and low-cost UV detectors. However, most of the reported NiO/n-Si UV detectors showed large dark current and low UV responsivity. Besides the defects in the silicon and NiO, the thickness of NiO film is an important factor that affects the performance. Herein, the NiO/n-Si UV photovoltaic detectors with different NiO film thicknesses were fabricated. The effect of NiO film thicknesses, such as 32, 74, 113, 147, 198 and 270 nm, on the performance of NiO/n-Si UV detector was investigated. A NiO/n-Si UV detector with a NiO thickness of 198 nm showed the excellent performance with a low dark current of 0.6 μA at -1 V and a high rectification ratio of 1.8×104 at ±1 V. The maximum responsivity (R) and detectivity (D*) of the device were 1.3 A/W and 5.7×1011 Jones, respectively, under 365 nm UV illumination. This work demonstrated that controlling NiO thickness has an essential influence on the performance optimization of NiO/n-Si UV photovoltaic detector.
Quantum dots infrared photodetector (QDIP) has found important applications due to its many advantages, such as long effective carrier life, low dark current, high operating temperature, facile preparation and low cost. In recent years, infrared photodetectors consisting of PbS and HgTe colloidal quantum dots (CQDs) have reported breakthroughs in the detection of short-wave infrared (SWIR) and mid-wave infrared (MWIR) demonstrating detectivity of 1×1013 Jones and 1×1011 Jones, respectively. However, these materials contain Pb and Hg elements, which are harmful to human and the environment. Therefore, the development of non-toxic quantum dot materials is highly desirable for QDIP. In this work, Ag2Se CQDs were studied for use in infrared photodetector. The novel CQDs have the advantages of low toxicity, good infrared optical properties, which can obtain adjustable infrared absorption due to its small bulk band gap of 0.15 eV, and biocompatibility etc. The Ag2Se CQDs were prepared by hot injection method and were characterized by Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), Fourier Transform Infrared spectrum (FTIR), Atomic Force Microscope (AFM) and X-ray Photoelectron Spectroscopy (XPS). These Ag2Se CQDs demonstrated good monodispersion, size uniformity and crystallization. Interestingly, the exciton peak appeared in the infrared band of 3-4 μm. Subsequently, Ag2Se CQDs photodetector was produced by spin coating the CQDs onto a 5 μm interdigital electrode. The device exhibited a low dark current of 1.3×10-6 mA with responsivity of 5 A/W and detectivity of 1.5×1013 Jones. The results of this work show that Ag2Se CQDs are expected to have potential applications in QDIP.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.