Density of states and carrier concentration in a 1d nanotube ion relationship of an arbitrary consider that the energy dispers id nanotube is given as 1 2m where v assume m can start from zero, which means the first sub-band corresponds to m 0 8x105 m/s, h planck's constant, d is the tube diameter, m is an integer (a) (15 points) plot density of states in this tube as a function of energy of energy for e < 2 ev for diameter d = 1 nm and 5 nm. the density of states for id is reported in no. per ev per length. (b) (15 points) calculate the carrier concentration in the nanotube at t = 300 k for equilibrium fermi level ev and 2 ev for d 5 nm. for the 1d case, carrier concentration is measured in no. per unit length of the tube

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

Apositive charge moves in the direction of an electric field. which of the following statements are true? check all that apply. check all that apply. 1.the potential energy associated with the charge decreases. 2. the electric field does positive work on the charge. 3. the electric field does negative work on the charge. 4. the potential energy associated with the charge increases. 5. the electric field does not do any work on the charge. 6. the amount of work done on the charge cannot be determined without additional information.

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =