| 1. |
- Chen, Xiren, et al.
(författare)
-
Bi-Induced Electron Concentration Enhancement Being Responsible for Photoluminescence Blueshift and Broadening in InAs Films
- 2019
-
Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 256:5
-
Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence (PL) study is conducted on InAs films molecular beam epitaxially grown on GaAs substrates with different Bi flux levels. A PL peak blueshift accompanied by linewidth broadening is found with the increase of Bi/As flux ratio, in contrast to the common Bi isoelectronic incorporation or surfactant effect. It is, with detailed lineshape analysis and the evidence of PL peak splitting in a magnetic filed, attributed to the electron concentration enhancement induced by Bi flux. The electron concentration in InAs film is evaluated, which is about 5-fold enhanced as Bi/As flux ratio rises up from 0 to 1x10(-3). The temperature dependence of the PL spectrum indicates that the carrier redistribution augments while the carrier-phonon Frohlich scattering weakens in InAs films with high Bi/As flux ratios. These findings reveal a novel Bi effect of electron concentration enhancement, and contribute to the basic knowledge of Bi in III-V semiconductors.
|
|
| 2. |
- Chen, X, et al.
(författare)
-
Modulated Photoluminescence Mapping of Long-Wavelength Infrared InAs / GaSb Type-II Superlattice: In-Plane Optoelectronic Uniformity
- 2021
-
Ingår i: Physical Review Applied. - 2331-7019. ; 15:4
-
Tidskriftsartikel (refereegranskat)abstract
- In-plane uniformity of narrow-gap semiconductor InAs/GaSb 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 InAs/GaSb 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.
|
|
| 3. |
- Chen, X, et al.
(författare)
-
Negative thermal quenching of below-bandgap photoluminescence in InPBi
- 2017
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
-
Tidskriftsartikel (refereegranskat)abstract
- This paper reports a temperature-dependent (10-280 K) photoluminescence (PL) study of below-bandgap electron-hole recombinations and anomalous negative thermal quenching of PL intensity in InP1- xBix (x = 0.019 and 0.023). Four PL features are well resolved by curve-fitting of the PL spectra, of which the energies exhibit different temperature dependence. The integral intensities of the two high-energy features diminish monotonically as temperature rises up, while those of the two low-energy features decrease below but increase anomalously above 180 K. A phenomenological model is established that the residual electrons in the final state of the PL transition transfer into nonradiative state via thermal hopping, and the thermal hopping produces in parallel holes in the final state and hence enhances the radiative recombination significantly. A reasonable interpretation of the PL processes in InPBi is achieved, and the activation energies of the PL quenching and thermal hopping are deduced. © 2017 Author(s).
|
|
| 4. |
- Dou, Cheng, et al.
(författare)
-
Photoluminescence Evolution with Deposition Thickness of Ge Nanostructures Embedded in GaSb
- 2022
-
Ingår i: Physica Status Solidi (B): Basic Research. - : Wiley. - 1521-3951 .- 0370-1972. ; 259:4
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, low-temperature and temperature-dependent photoluminescence (PL) measurements are carried out on highly tensile-strained Ge nanostructures embedded in GaSb matrix, and the effects of Ge deposition thickness are clarified. The direct-gap transition-related PL feature is successfully identified in the tensile-strained Ge nanostructures. While typical PL thermal quenching is observed for the tensile-strained Ge- and GaSb-related transitions in the samples with a Ge deposition being thinner than the critical thickness, a negative thermal quenching shows up for the GaSb interband transition in the samples with Ge deposition surpassing the critical thickness at which high-density nanoparticles form to relax the strain. A phenomenological thermal-injection model is established of electrons from the tensile-strained Ge layer to the GaSb matrix, the thermal quenching is accounted for, and a ladder-like function of the strain-relaxed Ge is clarified to favor the electron activation. The understanding of the effects of deposition thickness is helpful for the high-performance Ge-based light source for optoelectronic integration.
|
|
| 5. |
- Yan, Bing, et al.
(författare)
-
Bismuth-induced band-tail states in GaAsBi probed by photoluminescence
- 2019
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 114:5
-
Tidskriftsartikel (refereegranskat)abstract
- Band-tail states in semiconductors reflect the effects of material growth and/or treatment, affect the performance of optoelectronic applications, and are hence a well-concerned issue. Dilute-Bi GaAs is considered very competitive though the role of Bi is yet to be well clarified. We in this letter investigate the effect of Bi incorporation on the band-tail states in GaAs 1−x Bi x by excitation power- and magnetic field-dependent photoluminescence (PL) measurements at low temperatures. Three PL features are identified from a broad PL peak, which blue-shift monotonically with the increase in excitation power. None of the PL features correlate with single Bi-content free-exciton recombination, and band-tail filling rather than the donor-acceptor pair process is responsible for the power-induced blueshift. The density of band-tail states gets enhanced with the increase in the Bi incorporation level and affects the determination of Bi-induced bandgap reduction. The results indicate that joint analysis of excitation- and magneto-PL may serve as a good probe for band-tail states in semiconductors.
|
|
| 6. |
|
|
