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- Hou, Qichao, et al.
(författare)
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Different Doping Behaviors of Silicon in Zinc Blende and Wurtzite GaAs Nanowires : Implications for Crystal-Phase Device Design
- 2023
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Ingår i: ACS Applied Nano Materials. - 2574-0970. ; 6:13, s. 11465-11471
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Tidskriftsartikel (refereegranskat)abstract
- Crystal-phase engineering between zinc blende (ZB) and wurtzite (WZ) structures is becoming an important method in designing unique optoelectronic and electronic semiconductor devices. Doping to engineer their electric properties is thus of critical importance, but a direct experimental comparison in doping these two crystal structures is still missing. Nanowires (NWs) allow the coexistence of both structures due to their special growth mode. The differences in dopant incorporation between the two phases are studied here in GaAs NW shells that are coherently grown around the NWs, hence maintaining the crystal structure of the core. The Si dopant is observed to have a higher incorporation efficiency into the WZ structure due to a 2 times lower incorporation energy compared with that of the ZB structure. Besides, it can also be predicted that Si is more inclined toward Ga sites in both structures. Indeed, the As-site doping energy of the WZ structure is several orders of magnitude higher than that of Ga sites, allowing a lower doping compensation effect. This work provides useful information for doping control and hence designing crystal-phase devices.
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- Zhang, Yunyan, et al.
(författare)
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Highly Strained III-V-V Coaxial Nanowire Quantum Wells with Strong Carrier Confinement
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 13:5, s. 5931-5938
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Tidskriftsartikel (refereegranskat)abstract
- Coaxial quantum wells (QWs) are ideal candidates for nanowire (NW) lasers, providing strong carrier confinement and allowing close matching of the cavity mode and gain medium. We report a detailed structural and optical study and the observation of lasing for a mixed group-V GaAsP NW with GaAs QWs. This system offers a number of potential advantages in comparison to previously studied common group-V structures (e.g., AlGaAs/GaAs) including highly strained binary GaAs QWs, the absence of a lower band gap core region, and deep carrier potential wells. Despite the large lattice mismatch (∼1.7%), it is possible to grow defect-free GaAs coaxial QWs with high optical quality. The large band gap difference results in strong carrier confinement, and the ability to apply a high degree of compressive strain to the GaAs QWs is also expected to be beneficial for laser performance. For a non-fully optimized structure containing three QWs, we achieve low-temperature lasing with a low external (internal) threshold of 20 (0.9) μJ/cm2/pulse. In addition, a very narrow lasing line width of ∼0.15 nm is observed. These results extend the NW laser structure to coaxial III-V-V QWs, which are highly suitable as the platform for NW emitters.
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