带隙
衰减系数
超晶格
光子能量
材料科学
吸收(声学)
红外线的
光电子学
光学
凝聚态物理
光子
物理
作者
David R. Rhiger,E. P. Smith
摘要
We have studied infrared absorption near the bandgap energy in mid-wavelength (MWIR) III-V photon detectors built in the nBn configuration. The absorbing material is the InAs/InAsSb superlattice. We show that in a practical device near the infrared (IR) cutoff, the spectral response curve as a function of photon energy is proportional to the absorption coefficient, to a good approximation. Thus, in the near-gap range, the energy dependence of the device spectral response is a reliable proxy for the energy dependence of the absorption coefficient. We demonstrate this by means of an expansion of the Hovel equations in powers of the product of the absorption coefficient and hole diffusion length. One application of this result is that the point of maximum slope of the spectral response curve can be used to locate the true bandgap energy. This result also facilitates a study of absorption in the Urbach tail, which occurs at sub-gap energies. The temperature dependence of the Urbach steepness parameter was found to be consistent with the dominant phonon energy of InAs.
科研通智能强力驱动
Strongly Powered by AbleSci AI