# Question 3.6: A nonequilibrium electron transistor (NET) of the type shown......

A nonequilibrium electron transistor (NET) of the type shown schematically in Fig. 3.16 is to be designed for use in a high-speed switching application. In this situation the NET must have a high current drive capability. To achieve this one needs to ensure that spacecharging effects in the emitter and collector barriers are avoided. How would you modify the design of the NET to support current densities in excess of $10^{5} A cm^{-2}$ ?

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To avoid space-charging effects in the emitter and collector barriers of a NET, it is necessary to dope the emitter and collector barriers to an $n$-type impurity concentration density $n\gt j/e\upsilon _{av}$ , where $\upsilon _{av}$ is an appropriate average electron velocity in the barrier and $j$ is the current density. For typical values $\upsilon _{av} =10^{7} cm s^{-1}$ and $n\gt 10^{17} cm^{-3}$ this gives a maximum current density near $j=1.6\times 10^{5} A cm^{-2}$ .

Question: 3.7

## Using the method outlined in Section 3.4, write a computer program to solve the Schrödinger wave equation for the first four eigenvalues and eigenstates of an electron with effective mass me^∗ = 0.07×m0 confined to a rectangular potential well of width L = 10nm bounded by infinite barrier potential ...

We would like to use the method outlined in Sectio...
Question: 3.2

## (a) An electron in the conduction band of GaAs has an effective electron mass m^∗e = 0.07m0. Find the values of the first three energy eigenvalues, assuming a rectangular, infinite, one-dimensional potential well of width L = 10nm and L = 20nm. Find an expression for the difference in energy levels ...

(a) In this exercise we are to find the difference...
Question: 3.5

## (a) Consider a one-dimensional potential well approximated by a delta function in space so that V(x)=−bδ(x = 0). Show that there is one bound state for a particle of mass m, and find its energy and eigenstate. (b) Show that any one-dimensional delta function potential with V(x)=±bδ(x = 0) always ...

(a) Here we seek the eigenfunction and eigenvalue ...
Question: 3.4

## An asymmetric one-dimensional potential well of width L has an infinite potential energy barrier on the left-hand side and a finite constant potential of energy V0 on the right-hand side. Find the minimum value of L for which an electron has at least one bound state when V0 = 1 eV. ...

In this exercise, an $asymmetric$ one...
Question: 3.3