We demonstrate that van der Waals heterostructures based on CrI 3 , MoS 2 and a 3D semiconductor source may allow for all electrical control of spin polarized carrier injection into MoS 2 . We demonstrate this possibility using a simple resonant tunneling device structure and model it using the transfer matrix method. Our results show that electrically controlled spin polarized carrier injection is theoretically possible at low device bias. Index Terms-2D materials, CrI 3 , MoS 2 , In x Ga 1-x N, GaN, mixed dimensional structures, spin-polarization, van der waals heterostructures. Junxia Shi (Senior Member, IEEE) received the Ph.D. degree in electrical engineering from Cornell University, Ithaca, NY, in 2010. She is currently an Associate Professor with the Department of Electrical and Computer Engineering, University of Illinois at Chicago. She has authored and coauthored more than 70 articles and patents. Her research focuses on advanced compound semiconductor materials and devices, including gallium nitride-based power and RF devices, group III-V terahertz photodetectors, and TMDC 2D nanostructure-based valleytronics, qubits, chemical and biological sensors, etc. Professor Shi is a Senior Member of the IEEE.