Lattice‐Optimized GaAsSb/InP Heterojunction Toward Both Efficient Carrier Confinement and Thermal Dissipation

Abstract

High‐quality lattice‐matched and mismatched GaAs1–xSbx (0.37 < x < 0.57) epilayers are grown on InP by molecular beam epitaxy. The localized states are confirmed by the S‐shape behavior of the temperature‐dependent photoluminescence (PL). With the help of a model based on a redistribution process of localized excitons, the degree of carrier localization is estimated quantitatively. It is found that the degree of carrier localization reaches a maximum for the lattice‐matched sample with Sb = 47.7%, indicating that carrier localization effects are mainly due to compositional fluctuations. This result is corroborated by the power‐dependent PL. In addition, power‐dependent Raman measurements give a hint that the thermal conductivity of the lattice‐matched sample is ≈50% higher than that of lattice‐mismatched samples with Sb = 37.9% and 56.2%. Thus the abnormal S‐shape behavior (blue–redshift) that occurs in the power‐dependent PL from the lattice‐mismatched GaAsSb samples is attributed to both the lower degree of carrier localization and the enhanced laser heating effect caused by their smaller thermal conductivity.

Measurement of Thermal Conductivity of Suspended and Supported Single-Layer WS2 Using Micro-photoluminescence Spectroscopy

“…34 The temperature-dependent PL peak of the singlelayer WS 2 exhibits a red shift with temperature owing to the band gap shrinkage caused by the electron−phonon interaction and thermal expansion. 25 Both the corresponding shifts of the Raman and PL peaks with temperature are evident in Figure 2c, which exhibited a good linear relationship between them. The absolute values of the slope δω/δT (ω is the shift of Raman or PL peaks) are 6.47 × 10 −4 and 2236.6 × 10 −4 nm/K, respectively.…”

“…It was shown that the first-order Raman E 2 g 1 peak of the single-layer WS 2 shifts to a lower wavelength with an increase of temperature due to the phonon anharmonicity effect . The temperature-dependent PL peak of the single-layer WS 2 exhibits a red shift with temperature owing to the band gap shrinkage caused by the electron–phonon interaction and thermal expansion . Both the corresponding shifts of the Raman and PL peaks with temperature are evident in Figure c, which exhibited a good linear relationship between them.…”

“…Owing to the enhanced electron−phonon interaction and thermal expansion with temperature, there exists a shift of PL peaks as a function of temperature. 25 By monitoring the shift of PL peaks caused by temperature, the local temperature rise induced by the excitation laser is deduced.…”

“…An excitation laser was utilized for local heating and simultaneously to excite PL signals which come from the conduction band-to-valence band recombination of 2D materials. Owing to the enhanced electron–phonon interaction and thermal expansion with temperature, there exists a shift of PL peaks as a function of temperature . By monitoring the shift of PL peaks caused by temperature, the local temperature rise induced by the excitation laser is deduced.…”

Effect of Rapid Thermal Annealing on the Emission Properties in InGaAsSb/AlGaAsSb Multiple Quantum Wells

“…[14] Localized states as a common phenomenon in semiconductor materials have been investigated in GaAsSb alloy in detail. [15][16][17] It is also beneficial to the improvement of performance of optoelectronic devices. In our previous research, localized states characteristics in GaAsSb/AlGaAs multiple QWs (MQWs) [18] and GaAsSb epitaxial layers [19,20] were reported.…”