Pinpointing the Band Gap Energy of GaAs by Fitting the Transmissive Part of the Absorption Spectrum with Bootstrap Error

Optical absorption in semiconductors is one of the most basic yet complex properties in crystalline semiconductors. There have been decades of studies on optical absorption with specific efforts towards understanding the accuracy of measurements. However, the interdependence of the parameters employed in the fit routines poses challenges in calculating consistent and reliable errors associated with the process when the band tailing states are involved, which is unavoidable in all practical measurements. This work examines room-temperature absorption measurements in undoped GaAs to report consistent error bars employing a bootstrap resampling analysis. The results show that (1) the transmissive part of the measured absorption contains all the information about the fit parameters for the entire spectrum and (2) it is possible to utilize statistical bootstrap sampling to determine error bars when interdependent fit parameters are present in the fit model.