4. The effective mass ratios for an intrinsic semiconducting material as a function of absolute temperature T E (2000, 7

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4 The Effective Mass Ratios For An Intrinsic Semiconducting Material As A Function Of Absolute Temperature T E 2000 7 1 (96.39 KiB) Viewed 17 times

4. The effective mass ratios for an intrinsic semiconducting material as a function of absolute temperature T E (2000, 700) K are mm = 1.028 +6.11 x 10-4T - 3.09 x 10-12 mo тр 0.610+ 7.83 x 10-4T - 4.46 x 10-?T? (4) (3) mo where mo is electron rest mass. Let the band gap energy of the material in the tem- perature range 200 ST < 700°K be leV. Determine the electron concentration n in the conduction band and hole concentration p in the valence band (i) if Ez is 0.4852 eV above valence band edge and T = 700° K. What is the product np? (10 points) (ii) if Ep is 0.5075 eV below the conduction band edge and T = 300° K. What is the product np? (10 points) (iii) If the electron and hole mobilities are fin = 1,800 cm?/V-s and Hp = 1,200 cm?/V- s, respectively, determine the conductivity of the material using the concentra- tions from part (4ii). (10 points) (iv) If now the material is doped with donor atoms at a concentration Na = 2 x 1015 cm, recalculate n, p and the product np at the room temperature. Assume that donors are fully ionized at room temperature. (20 points)