Red (R), Green (G) and Blue (B) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different

Q. Red (R), Green (G) and Blue (B) Light Emitting Diodes (LEDs) were fabricated using p-n junctions of three different inorganic semiconductors having different band-gaps. The built- in voltages of red, green and blue diodes are VR, VG and VB, respectively. Assume donor and acceptor doping to be the same (NA and ND, respectively) in the p and n sides of all the three diodes.

Which one of the following relationships about the built-in voltages is TRUE?

A. VR > VG > VB

B. VR < VG < VB

C. VR = VG = VB

D. VR > VG < VB

Ans: V_R < V_G < V_B