Modulated Photoluminescence Mapping of Long-Wavelength Infrared <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mrow><mml:mi>In</mml:mi><mml:mi>As</mml:mi></mml:mrow></mml:math>/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mrow><mml:mi>Ga</mml:mi><mml:mi>Sb</mml:mi></mml:mrow></mml:math> Type-II Superlattice: In-Plane Optoelectronic Uniformity
Xiren Chen, Liangqing Zhu, Yanchao Zhang, Fan Zhang, Shumin Wang, Jun Shao
Abstract
In-plane uniformity of narrow-gap semiconductor $\mathrm{In}\mathrm{As}$/$\mathrm{Ga}\mathrm{Sb}$ type-II superlattice (T2SL) wafer is a crucial yet hard-to-evaluate prerequisite for high-performance long-wavelength infrared optoelectronic device applications of, e.g., focal-plane-array (FPA) photodetectors. In this work, we report a modulated photoluminescence-mapping (PL-mapping) study of $\mathrm{In}\mathrm{As}$/$\mathrm{Ga}\mathrm{Sb}$ T2SL in long-wavelength infrared range with a spatial resolution of a typical FPA-pixel scale. Spatial distributions are analyzed of PL-peak energy, linewidth, and integral intensity, which indicate a high in-plane uniformity of effective band gap but a considerable fluctuation of radiative recombination. The in-plane distributions of effective carrier lifetime and Shockley-Read-Hall defect concentration are evaluated, with the aid of a model that takes into account the pumping power dependence of the PL integral intensity. The results reveal a considerable in-plane nonuniformity of the optoelectronic response that may restrict the performance of the derivative FPA photodetector, and indicate the modulated PL mapping of a good pathway particularly for uniformity analysis of long-wavelength infrared FPA semiconductors.