a) The shortcircuit current density Use] of a solar cell can be calculated from the measured external quantum efficiency EQHE} using the expression Js'r' : CL?) 'raiwr ('9) EQE() d5 Lb'--uH Note: where Inside] is the spectral irradiance incident upon the cell under AMI] {with x=DJ orAM1.5d (with x=l.5d], E is the incident photon energy, and :1 is the band gap of the semiconductor. I Find the functional form of C in the integral given above that will make the above integral true. (Hint: unit analysis will, again, be helpful}. b) Using the functional fit for the AMD spectral irradiance Ismnle] found in Question 1 part {e}, plot the shortcircuit current density from part {a} as a function of band gap energy a in units of maltfcm2 . Be careful with unit conversions! Typical band gap energies may range from 0.0 5.0 e'v'. Assume an external quantum efficiency of 1.0 [that is, for every absorbed photon, an electronhole pair is created}. 0 Re Recall: The functional fit for AMD spectral irradiance IAMU{E) has the form: bl Using the functional fit for the AMD spectral irradiance Ismnle) found in Question 1 part {e}, plot the shortcircuit current density from part {a} as a function of band gap energy D. in units of mn'cm2 . Be careful with unit conversions! Typical band gap energies may range from 0.0 5.0 eV. Assume an external quantum efficiency of 1.0 [that is, for every absorbed photon, an electronhole pair is created}. 0 Re- Recall: The functional fit for AMD spectral irradiance IAMdE) has the form: A 5:3 1".4.uo(3} = W c) Using the information calculated in part (b) above, estimate how solar cell efficiency changes as a function of band gap energy. To do so, assume that the output voltage of the device is equal to the band gap energy per fundamental unit of charge (Le. Vamput=u l. The power per area (Le. efficiency} produced will then he Jscx'v'amput, where J5: is the short-circuit current {equivalent to light generated current per unit area], which was calculated in part {a} 0 Plot this estimated device efficiency vs. band gap energy. d) On the plot created in part (cl, please mark the estimated maximum efficiencies ofthe following materials according to their band gap energy: c-Si, Ge, aSi:H. e} Repeat part (c) and part (d), numerically, using data for the AM1.5d spectral irradiance