Maxim Ryzhii
University of Aizu
Dr. M. Ryzhii received the M.S. degree in quantum electronics from the Moscow Institute of Physics and Technology, Russia, in 1992, and the D.Eng.degree in physical electronics from the Tokyo Institute of Technology, Japan, 2001. From 1993, he has been with the University of Aizu, Aizu-Wakamatsu, Japan, where he is currently an Associate Professor. His research activity includes physics and computer modeling of optoelectronic and terahertz nanostructure devices, and computational modeling of biophysical systems. He is the author or coauthor of more than 120 journal publications. Dr. Ryzhii is a member of the APS and IEEE (senior).
Creation of the heterostructures based on the van der Waals (vdW) materials [1] with graphene layers (GLs) opens up prospects in implementation of novel optoelectronics devices. Contrary to the traditional epitaxially grown heterostructures, in the vdW heterostructures the layers with different lattice constants can be stacked together because of weak inter-layer bonding. As a result, a wide family of the vdW materials could form heterostructures with required properties. In this report, we analyze the concept and consider the characteristics of the recently proposed infrared photodetectors based on the vertical heterostructures with the vdW material’s barrier layers, GLs, and n-type emitter and collector contacts [2]. The vdW/GL infrared photodetectors in question can be made using a single or multiple GLs sandwiched between the vdW material barrier layers (hBN, WS2, WSe2, and similar materials).
Using the developed analytical device model we calculate the vdW/GL infrared photodetector responsivity and dark current detectivity as functions of the energy of incident infrared photons and the structural parameters.
The doping engineering can be used for the optimization of vdW/GL infrared photodetectors operating in different radiation spectrum ranges.
We compare the responsivity, detectivity, and performance of the vertical vdW/GL infrared photodetectors with other photodetectors based on the lateral single– and multiple–GL heterostructures with p–i–n junctions [3] and with the vertical single– and multiple–quantum–well infrared photodetectors (QWIPs) using the intersubband transitions. As shown, the proposed vertical vdW/GL infrared photodetectors might exhibit the following advantages: (i) sensitivity to the normally incident infrared radiation due to the use of the interband transitions in the gapless GLs, (ii) a higher probability of the electron photoexcitation from the GLs, (iii) a lower probability of the capture of the electrons propagating above the barriers in into the GLs, and (iv) a weaker dark current promoting higher detectivity values.
References
[1] A. K. Geim and I. V. Grigoreva, Nature 499, 419 (2013).
[2] V. Ryzhii, et al., Infrared Phys. Technol. (2017), in press.
[3] V. Ryzhii, et al., J. Appl. Phys. 107, 054512 (2010).
Optoelectronic nanodevices: laser, LEDs, nano antennas… , Carbon & graphene nanostructures
