Spintronics is the vision of using the spin of the electrons instead of its charge to perform information storage and processing. These spin based devices has the potential to make the future computers non-volatile, faster, with memory and processing integrated into a single chip, all with reduced energy consumption. A profound impact on the development of spintronics could come from exploiting spin degree of freedom in the main stream semiconductor like silicon at room temperature.The first goal of this proposal is to establish a physical understanding of the fundamental processes of efficient generation, sensitive detection, and effective manipulatipon of spin current in silicon. Spin polarization in silicon will be created by different methods such as - electrical spin injection, thermal spin injection, spin pumping, and spin Hall effect using ferromagnet/silicon heterostructures. Detection of the created spin polarization will be performed by combination of different techniques both in local and non-local geometry, for example by use of spin-valve measurements, Hanle measurements and inverse spin Hall effect measurements. Finally the manipulation of such spin polarization will be controlled by magnetic field and electric field. The aim of this proposal is to achieve all these operations in both n-type and p-type silicon at room temperature.The second goal is to implement silicon spintronic devices by integrating different functionalities obtained from our first goal. While relevant for the development of a spin based transistor, this work aims to go well beyond that, aiming for new routes to create and control spins in silicon nanostructures. For realization of this we propose to develop novel approaches for fabrication of silicon based nano-spintronic devices and design new transport measurement techniques which will lead to these fundamental physics experiments, and possibly new applications.