TRANSPORT PROPERTIES OF TRANSITION METAL DOPED INDIUM PHOSPHIDE

Abstract

This dissertation work concerns with the transport properties of transition metal doped Indium Phosphide (InP). The transition metals considered in present work are Iron (Fe), Vanadium (V), Ruthenium (Ru) and Cobalt (Co). The ultimate aim to dope Indium Phosphide with transition metals is to make it semi-insulating in nature. Substrate, over which epitaxial layer is grown, needs to be insulated from the devices fabricated over it for better functioning. InP works as an useful substrate for growing epitaxial layer of some important ternary and quaternary compound semiconductors, since it is lattice matched with some of them like GaInAs and GaInAsP with specific compositions. It can be understood with the help of Fig. 1.1. Fig. 1.1 illustrates the energy band gap Eg as a function of lattice constant a' for several III-V ternary compounds as they are varied over their composition ranges'. For example, as the ternary compound InGaAs is varied by choice of composition on the column III sub lattice from InAs to GaAs, the band gap changes from 0.36 to 1.43 eV while the lattice constant of the crystal varies from 6.06 A for InAs to 5.65 A GaAs. Clearly, we cannot grow this ternary compound over the entire composition range on a particular binary substrate, which has a fixed lattice constant. However, it is possible to grow a specific composition of InGaAs on InP substrate..