“…The energy gap ( E g ) can be determined using the following formula
17,35 :
where, A is the quality factor associated with transition probability, hν is the photon energy, α is the absorption coefficient, and s is linked to the prevailing electronic transition for direct‐allowed, direct‐forbidden, indirect‐allowed, or indirect‐forbidden transitions, which takes values of 1/2, 3/2, 2, or 3, respectively. The E g , is obtained by the linear intersection of the curve with the x‐axis of the plot ( α hν) 2 versus hν, with A representing the slope of the straight line.…”