Near band edge absorption spectra of narrow-gap III–V semiconductor alloys

Near band edge absorption spectra of the narrow-gap semiconductor alloys InxTl1−xP, InxTl1−xAs, and InxTl1−xSb were calculated and compared with those of HgxCd1−xTe. To test accuracy, we compared the calculated absorption spectra in GaAs with experimental results and found good agreement. Within 50 meV from the absorption edge, the absorption coeffi cient of InxTl1−xP is found to have about the same magnitude as that in HgxCd1−xTe and GaAs, whereas that in InxTl1−xAs and InxTl1−xSb is much smaller. This result and other merits found from previous studies indicate that InxTl1−xP has a potential to compete favorably with HgxCd1−xTe for long-wavelength infrared applications.