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Variable‐angle spectroscopic ellipsometry is used to determine the room temperature complex refractive index of molecular beam epitaxy grown GaSb_1−xBi_xfilms withx ≤ 4.25% over a spectral range of 0.47–6.2 eV. By correlating to critical points in the extinction coefficientk, the energies of several interband transitions are extracted as functions of Bi content. The observed change in the fundamental bandgap energy (E₀, −36.5 meV per %Bi) agrees well with previously published values; however, the samples examined here show a much more rapid increase in the spin‐orbit splitting energy (Δ₀, +30.1 meV per Bi) than previous calculations have predicted. As in the related GaAsBi, the energy of transitions involving the top of the valence band are observed to have a much stronger dependence on Bi content than those that do not, suggesting the valence band maximum is most sensitive to Bi alloying. Finally, the effects of surface droplets on both the complex refractive index and the critical point energies are examined. 

Two- or three-dimensionally patterned subwavelength structures, also known as metamaterials, have the advantage of arbitrarily engineerable optical properties. In thermophotovoltaic (TPV) applications, metamaterials are commonly used to optimize the emitter’s radiation spectrum for various source temperatures. The output power of a TPV device is proportional to the photon flux, which is proportional to the emitter size. However, using 2D or 3D metamaterials imposes challenges to realizing large emitters since fabricating their subwavelength features typically involves complicated fabrication processes and is highly time-consuming. In this work, we demonstrate a large-area (78 cm2) thermal emitter. This emitter is simply fabricated with one-dimensional layers of silicon (Si) and chromium (Cr), and therefore, it can be easily scaled up to even larger sizes. The emissivity spectrum of the emitter is measured at 802 K, targeting an emission peak in the mid-infrared. The emissivity peak is ∼0.84 at the wavelength of 3.75 μm with a 1.2 μm bandwidth. Moreover, the emission spectrum of our emitter can be tailored for various source temperatures by changing the Si thickness. Therefore, the results of this work can lead to enabling TPV applications with higher output power and lower fabrication cost. 

􀀞􀀞􀀞􀀇􀀫􀀁􀁄􀀶􀀾􀀺􀀴􀁀􀀿􀀵􀁆􀀴􀁅􀁀􀁃􀁄􀀁􀀹􀀲􀁇􀀶􀀁􀀳􀁃􀁀􀀲􀀵􀀁􀁆􀁄􀀶􀁄􀀁􀀺􀀿􀀁􀁀􀁁􀁅􀁀􀀶􀀽􀀶􀀴􀁅􀁃􀁀􀀿􀀺􀀴􀁄􀀁􀀵􀁆􀀶􀀁􀁅􀁀􀀁􀁅􀀹􀀶􀀺􀁃􀀁􀀵􀀺􀁃􀀶􀀴􀁅􀀁􀀳􀀲􀀿􀀵􀀁􀀸􀀲􀁁􀁄􀀁􀀲􀀿􀀵􀀁􀀹􀀺􀀸􀀹􀀁􀀴􀀲􀁃􀁃􀀺􀀶􀁃􀀁􀀾􀁀􀁅􀀺􀀽􀀺􀁅􀀺􀀶􀁄􀀈􀀁􀀜􀀲􀀖􀁄􀀃􀀋􀀇 􀁉􀀄􀀗􀀺􀁉􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀁉􀀜􀀲􀀃􀀋􀀇􀁉􀀄􀀖􀁄􀀁􀁅􀀶􀁃􀀿􀀲􀁃􀁊􀀁􀀲􀀽􀀽􀁀􀁊􀁄􀀁􀀲􀁃􀀶􀀁􀁀􀀷􀀁􀀺􀀿􀁅􀀶􀁃􀀶􀁄􀁅􀀁􀀷􀁀􀁃􀀁􀀽􀀺􀀸􀀹􀁅􀀁􀀶􀀾􀀺􀁅􀁅􀀺􀀿􀀸􀀆􀀁􀀽􀀺􀀸􀀹􀁅􀀁􀀲􀀳􀁄􀁀􀁃􀀳􀀺􀀿􀀸􀀁􀀲􀀿􀀵􀀁􀁀􀁅􀀹􀀶􀁃􀀁􀀲􀁁􀁁􀀽􀀺􀀴􀀲􀁅􀀺􀁀􀀿􀁄􀀁􀀃􀀶􀀈􀀸􀀈 􀀴􀁀􀀾􀀾􀁆􀀿􀀺􀀴􀀲􀁅􀀺􀁀􀀿􀀁􀀽􀀲􀁄􀀶􀁃􀁄􀀆􀀁􀁁􀀹􀁀􀁅􀁀􀁇􀁀􀀽􀁅􀀲􀀺􀀴􀁄􀀆􀀁􀀲􀀿􀀵􀀁􀀹􀀺􀀸􀀹􀀁􀁄􀁁􀀶􀀶􀀵􀀁􀁅􀁃􀀲􀀿􀁄􀀺􀁄􀁅􀁀􀁃􀁄􀀄􀀁􀀺􀀿􀀁􀁅􀀹􀀶􀀁􀀺􀀿􀀷􀁃􀀲􀁃􀀶􀀵􀀁􀁄􀁁􀀶􀀴􀁅􀁃􀁆􀀾􀀁􀀵􀁆􀀶􀀁􀁅􀁀􀀁􀁅􀀹􀀶􀀺􀁃􀀁􀀵􀀶􀀴􀁃􀀶􀀲􀁄􀀶􀀵􀀁􀀳􀀲􀀿􀀵􀀸􀀲􀁁 􀁃􀀶􀀽􀀲􀁅􀀺􀁇􀀶􀀁􀁅􀁀􀀁􀀜􀀲􀀖􀁄􀀈􀀁􀀬􀀹􀀺􀀽􀀶􀀁􀀜􀀲􀀖􀁄􀀁􀀹􀀲􀁄􀀁􀀳􀀶􀀶􀀿􀀁􀀶􀁉􀁅􀀶􀀿􀁄􀀺􀁇􀀶􀀽􀁊􀀁􀁄􀁅􀁆􀀵􀀺􀀶􀀵􀀆􀀁􀁅􀀹􀀶􀀁􀁀􀁁􀁅􀀺􀀴􀀲􀀽􀀁􀁁􀁃􀁀􀁁􀀶􀁃􀁅􀀺􀀶􀁄􀀁􀁀􀀷􀀁􀀜􀀲􀀖􀁄􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀜􀀲􀀖􀁄􀀁􀀲􀁃􀀶􀀁􀀽􀀶􀁄􀁄 􀀵􀁀􀀴􀁆􀀾􀀶􀀿􀁅􀀶􀀵􀀁􀀲􀀿􀀵􀀁􀁄􀀹􀁀􀁈􀀁􀁄􀀺􀀸􀀿􀀺􀀷􀀺􀀴􀀲􀀿􀁅􀀁􀁇􀀲􀁃􀀺􀀲􀁅􀀺􀁀􀀿􀀁􀁈􀀺􀁅􀀹􀀁􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀁􀀴􀁀􀀿􀁅􀀶􀀿􀁅􀀁􀁃􀀶􀁄􀁁􀀶􀀴􀁅􀀺􀁇􀀶􀀽􀁊􀀈 􀀩􀀹􀀺􀁄􀀁􀁄􀁅􀁆􀀵􀁊􀀁􀀴􀀹􀀲􀁃􀀲􀀴􀁅􀀶􀁃􀀺􀁋􀀶􀀵􀀁􀁅􀀹􀀶􀀁􀁀􀁁􀁅􀀺􀀴􀀲􀀽􀀁􀁁􀁃􀁀􀁁􀀶􀁃􀁅􀀺􀀶􀁄􀀁􀁀􀀷􀀁􀀜􀀲􀀖􀁄􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀜􀀲􀀖􀁄􀀁􀀷􀀺􀀽􀀾􀁄􀀁􀁀􀀷􀀁􀁇􀀲􀁃􀁊􀀺􀀿􀀸􀀁􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀁􀀴􀁀􀀾􀁁􀁀􀁄􀀺􀁅􀀺􀁀􀀿􀀁􀁆􀁄􀀺􀀿􀀸􀀁 􀁇􀀲􀁃􀀺􀀲􀀳􀀽􀀶􀀁􀀲􀀿􀀸􀀽􀀶􀀁􀁄􀁁􀀶􀀴􀁅􀁃􀁀􀁄􀀴􀁀􀁁􀀺􀀴􀀁􀀶􀀽􀀽􀀺􀁁􀁄􀁀􀀾􀀶􀁅􀁃􀁊􀀁􀀃􀀫􀀖􀀨􀀚􀀄􀀁􀀺􀀿􀀁􀀲􀀁􀁃􀀲􀀿􀀸􀀶􀀁􀁀􀀷􀀁􀁅􀀶􀀾􀁁􀀶􀁃􀀲􀁅􀁆􀁃􀀶􀁄􀀁􀀷􀁃􀁀􀀾􀀁􀀌􀀏􀀁􀁖􀀘􀀁􀁑􀀁􀀍􀀊􀀊􀀁􀁖􀀘􀀈􀀁􀀜􀀲􀀖􀁄􀀗􀀺􀀁􀀷􀀺􀀽􀀾􀁄􀀁􀁈􀀶􀁃􀀶􀀁 􀀸􀁃􀁀􀁈􀀿􀀁􀀳􀀶􀁅􀁈􀀶􀀶􀀿􀀁􀀍􀀈􀀍􀀂􀀁􀀲􀀿􀀵􀀁􀀐􀀈􀀏􀀂􀀁􀀳􀀺􀁄􀀾􀁆􀁅􀀹􀀈􀀁􀀩􀀽􀀜􀀲􀀖􀁄􀀁􀀷􀀺􀀽􀀾􀁄􀀁􀁈􀀶􀁃􀀶􀀁􀀸􀁃􀁀􀁈􀀿􀀁􀀳􀀶􀁅􀁈􀀶􀀶􀀿􀀁􀀋􀀈􀀑􀀂􀀁􀀲􀀿􀀵􀀁􀀌􀀈􀀑􀀂􀀁􀁅􀀹􀀲􀀽􀀽􀀺􀁆􀀾􀀈􀀁􀀢􀁀􀀵􀀶􀀽􀀺􀀿􀀸􀀁􀁆􀁄􀀺􀀿􀀸􀀁􀀲􀀁 􀁄􀁆􀁁􀀶􀁃􀁁􀁀􀁄􀀺􀁅􀀺􀁀􀀿􀀁􀁀􀀷􀀁􀀜􀀲􀁆􀁄􀁄􀀺􀀲􀀿􀀁􀁀􀁄􀀴􀀺􀀽􀀽􀀲􀁅􀁀􀁃􀁄􀀁􀀷􀀺􀁅􀀁􀁅􀁀􀀁􀁅􀀹􀀶􀀁􀀵􀀺􀀶􀀽􀀶􀀴􀁅􀁃􀀺􀀴􀀁􀀷􀁆􀀿􀀴􀁅􀀺􀁀􀀿􀁄􀀁􀁀􀀷􀀁􀁄􀀲􀀾􀁁􀀽􀀶􀀁􀀽􀀲􀁊􀀶􀁃􀁄􀀁􀁈􀀲􀁄􀀁􀁆􀁄􀀶􀀵􀀁􀁅􀁀􀀁􀁄􀀶􀁁􀀲􀁃􀀲􀁅􀀶􀀁􀀷􀀺􀀽􀀾􀀁􀁀􀁁􀁅􀀺􀀴􀀲􀀽􀀁 􀁁􀁃􀁀􀁁􀀶􀁃􀁅􀀺􀀶􀁄􀀁􀀷􀁃􀁀􀀾􀀁􀁅􀀹􀀶􀀁􀁁􀁄􀀶􀁆􀀵􀁀􀁀􀁁􀁅􀀺􀀴􀀲􀀽􀀁􀁁􀁃􀁀􀁁􀀶􀁃􀁅􀀺􀀶􀁄􀀁􀁀􀀷􀀁􀁅􀀹􀀶􀀁􀁄􀀲􀀾􀁁􀀽􀀶􀀈􀀁 􀀩􀀹􀀶􀀁􀀲􀀿􀀲􀀽􀁊􀁄􀀺􀁄􀀁􀀺􀀿􀀁􀁅􀀹􀀺􀁄􀀁􀁄􀁅􀁆􀀵􀁊􀀁􀀵􀀺􀁃􀀶􀀴􀁅􀀽􀁊􀀁􀀴􀁀􀀾􀁁􀀲􀁃􀀶􀁄􀀁􀁅􀀹􀀶􀀁􀀺􀀿􀀴􀀽􀁆􀁄􀀺􀁀􀀿􀀁􀁀􀀷􀀁􀁅􀀹􀀶􀀁􀁅􀁈􀁀􀀁􀀽􀀲􀁃􀀸􀀶􀁄􀁅􀀁􀀞􀀞􀀞􀀇􀀫􀀁􀀴􀁀􀀿􀁄􀁅􀀺􀁅􀁆􀀶􀀿􀁅􀀁􀀲􀁅􀁀􀀾􀁄􀀆􀀁􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀈􀀁 􀀘􀁀􀀾􀁁􀀲􀁃􀀺􀁄􀁀􀀿􀀁􀁀􀀷􀀁􀁅􀀹􀀶􀀁􀁃􀀶􀀷􀁃􀀲􀀴􀁅􀀺􀁇􀀶􀀁􀀺􀀿􀀵􀀶􀁉􀀁􀀲􀀿􀀵􀀁􀀲􀀳􀁄􀁀􀁃􀁁􀁅􀀺􀁀􀀿􀀁􀀴􀁀􀀶􀀷􀀷􀀺􀀴􀀺􀀶􀀿􀁅􀀁􀁀􀀷􀀁􀁄􀀲􀀾􀁁􀀽􀀶􀁄􀀁􀁈􀀲􀁄􀀁􀀵􀁀􀀿􀀶􀀁􀁀􀁇􀀶􀁃􀀁􀀲􀀁􀁄􀁁􀀶􀀴􀁅􀁃􀀲􀀽􀀁􀁃􀀲􀀿􀀸􀀶􀀁􀁀􀀷􀀁􀀊􀀈􀀏􀀁􀀶􀀫􀀁􀁅􀁀􀀁􀀏􀀁 􀀶􀀫􀀁􀀃􀀌􀀏􀀊􀀁􀀿􀀾􀀁􀁅􀁀􀀁􀀌􀀏􀀊􀀊􀀁􀀿􀀾􀀄􀀈􀀁􀀩􀀹􀀺􀁄􀀁􀁃􀀶􀀸􀀺􀁀􀀿􀀁􀀵􀀺􀁄􀁁􀀽􀀲􀁊􀁄􀀁􀁅􀀹􀀶􀀁􀀲􀀳􀁄􀁀􀁃􀁁􀁅􀀺􀁀􀀿􀀁􀀶􀀵􀀸􀀶􀀁􀀴􀁀􀁃􀁃􀀶􀁄􀁁􀁀􀀿􀀵􀀺􀀿􀀸􀀁􀁅􀁀􀀁􀁅􀀹􀀶􀀁􀀳􀀲􀀿􀀵􀀸􀀲􀁁􀀁􀁀􀀷􀀁􀁅􀀹􀀶􀀁􀀾􀀲􀁅􀀶􀁃􀀺􀀲􀀽􀀆􀀁􀁈􀀹􀀺􀀴􀀹􀀁 􀀺􀁄􀀁􀁅􀀹􀀶􀀿􀀁􀀴􀁀􀁃􀁃􀀶􀀽􀀲􀁅􀀶􀀵􀀁􀁅􀁀􀀁􀁅􀀹􀀶􀀁􀀺􀀿􀀴􀁀􀁃􀁁􀁀􀁃􀀲􀁅􀀺􀁀􀀿􀀁􀁀􀀷􀀁􀀗􀀺􀀁􀀲􀀿􀀵􀀁􀀩􀀽􀀁􀀺􀀿􀀁􀁅􀀹􀀶􀀁􀁄􀀲􀀾􀁁􀀽􀀶􀁄􀀈􀀁􀀩􀀹􀀺􀁄􀀁􀀴􀀹􀀲􀁃􀀲􀀴􀁅􀀶􀁃􀀺􀁋􀀲􀁅􀀺􀁀􀀿􀀁􀀲􀀽􀀽􀁀􀁈􀁄􀀁􀀷􀁀􀁃􀀁􀀳􀀶􀁅􀁅􀀶􀁃􀀁􀀾􀁀􀀵􀀶􀀽􀀺􀀿􀀸􀀁􀁀􀀷􀀁 􀁅􀀹􀀶􀁄􀀶􀀁􀀲􀀽􀀽􀁀􀁊􀁄􀀁􀀷􀁀􀁃􀀁􀀳􀁀􀁅􀀹􀀁􀀲􀀁􀀷􀁆􀀿􀀵􀀲􀀾􀀶􀀿􀁅􀀲􀀽􀀁􀁆􀀿􀀵􀀶􀁃􀁄􀁅􀀲􀀿􀀵􀀺􀀿􀀸􀀁􀁀􀀷􀀁􀁅􀀹􀀶􀀺􀁃􀀁􀁁􀁃􀁀􀁁􀀶􀁃􀁅􀀺􀀶􀁄􀀁􀀲􀀿􀀵􀀁􀀷􀁀􀁃􀀁􀁅􀀹􀀶􀀺􀁃􀀁􀀺􀀿􀀴􀀽􀁆􀁄􀀺􀁀􀀿􀀁􀀺􀀿􀀁􀀷􀁆􀁅􀁆􀁃􀀶􀀁􀀵􀀶􀁇􀀺􀀴􀀶􀁄􀀈􀀁 

Abstract Driven by tensile strain, GaAs quantum dots (QDs) self-assemble on In_0.52Al_0.48As(111)A surfaces lattice-matched to InP substrates. In this study, we show that the tensile-strained self-assembly process for these GaAs(111)A QDs unexpectedly deviates from the well-known Stranski-Krastanov (SK) growth mode. Traditionally, QDs formed via the SK growth mode form on top of a flat wetting layer (WL) whose thickness is fixed. The inability to tune WL thickness has inhibited researchers’ attempts to fully control QD-WL interactions in these hybrid 0D-2D quantum systems. In contrast, using microscopy, spectroscopy, and computational modeling, we demonstrate that for GaAs(111)A QDs, we can continually increase WL thickness with increasing GaAs deposition, even after the tensile-strained QDs (TSQDs) have begun to form. This anomalous SK behavior enables simultaneous tuning of both TSQD size and WL thickness. No such departure from the canonical SK growth regime has been reported previously. As such, we can now modify QD-WL interactions, with future benefits that include more precise control of TSQD band structure for infrared optoelectronics and quantum optics applications. 

Antenna coupled detectors break the intrinsic tradeoff between signal and noise by “collecting over a large area” and “detecting over a small area”. Most antenna coupled detectors in the infrared rely on a metal resonator structure. However, there are losses associated with metallic structures. We have demonstrated a novel long-wave infrared (LWIR) detector that combines a dielectric resonator antenna with an antimonide-based absorber. The detector consists of a 3D, subwavelength InAsSb absorber embedded in a resonant, cylindrical dielectric resonator antenna made of amorphous silicon. This architecture enables the antimonide detection element to shrink to deep subwavelength dimensions, thereby reducing its thermal noise. It is important to note that this concept only applies when (a) the detector noise is limited by bulk noise mechanisms with negligible surface leakage currents and (b) the dominant source of current in the device is due to dark current (such as diffusion) that scales with the volume of the detector. The dielectric resonator enhances the collection of photons with its resonant structure that couples incident radiation to the detector. We will present results on the absorption in structures with and without the dielectric resonator antenna. The signal to noise enhancement in the LWIR photodiodes integrated with the dielectric resonator antenna using radiometric characterization will be discussed.