Question

What are the different techniques that you can use to control the barrier height ? Use necessary equations and graphs to support your answer.

Answer 1

There are many barrier as in Quantum mechanics there is potential barrier having height to as shown in figure having width as V. Ľ X20 xea - There is barrier height in electronics die in semiconductor. We know in p-n junction there is a barrier between two region (p and n). -> There is another Schottky barrier Height (SBU) on the atomic structure of the metal-semicon- ductor (MS) interface. In case of metal -semiconductor the barrier height may be determined from graph of 1/C² as a function of applied reverse blas. - The barrier height is given by P = Vbi tem + k l - 80 to where Voi built in potential od potential change due to image force In = kI en ND-NA and Ne* alamatan) Y No number of donos atoms meffective q Nc * NAY number mess of accepter atom

E Metal Ec 74 Ev →X Semiconductor =) barrier height is the potential difference between Ep the fermi energy of the metal and the band edge where the majority carrier reside. -> To control the barrier height the simple approach is to make use of the empirical dependence of the magnitude of the SBH on the interface structure. -> A second approach involves the insertion of an inorganic interface layer between the semiconductor and the metal, in order to modify the SBH( Semiconductor / Schottky barrier heght). This has been accomplished by introduction of a very thin layer, typically sub-monolayer to a few monolayers of chalcogen. - The third technique to SBH modification. makes use of the dipole moment of organic molecules. 10o = Qm+ q Ng to it tog=0 where am surface charge density, Qit interface-trapped qNf oxide fixed charge Qs for semiconductor