-
GeSn合金作为一种新型硅基光电材料, 因其带隙可调特性以及兼容硅基CMOS工艺等优点, 在红外光子学领域展现出显著的应用潜力. 尽管GeSn激光器在低温条件下的实验性能已得到初步验证, 但该器件的优化与实际应用仍面临着对材料特性的认识尚不充分等挑战. 本文针对GeSn合金在红外光子学应用中存在的载流子动力学机制不明等问题, 通过建立包含能带参数、非平衡态载流子输运和辐射复合的唯象理论模型, 系统研究了变温条件下热激发和声子辅助过程对GeSn合金直接带自发发射影响的机理. 研究结果表明, GeSn合金ΓCBM与LCBM能谷间的载流子转移过程表现出显著的组分依赖性: 对于Sn组分小于10%的低组分GeSn合金, 温度诱导的LCBM→ΓCBM电子转移占主导, 导致直接带发光效率随着温度的升高而增强; 而在Sn组分在10%—20%的高组分GeSn合金中, ΓCBM→LCBM的电子逃逸过程更为显著, 造成直接带发光效率随着温度的升高而降低. 改进型Arrhenius模型分析载流子谷间输运与辐射复合的竞争机制进一步表明, 热激发和声子辅助对ΓCBM能谷电子注入或者逃逸均有促进作用, 是提升或者降低GeSn合金直接带隙辐射复合效率的关键因素. GeSn合金自发发射谱的峰位红移主要源于带隙收缩效应; 同时声子辅助过程会降低载流子能量分布的离散性, 导致直接带发射谱谱线窄化效应明显. 量化研究结果进一步揭示了GeSn合金中载流子的热激发和声子辅助对直接带隙发光影响的机制, 可为其在红外光电器件中的性能调控提供理论参考.GeSn alloy, as a novel silicon-based optoelectronic material, exhibits significant application potential in the field of infrared photonics due to its tunable bandgap properties and compatibility with silicon-based CMOS processes. Although the experimental performance of GeSn laser under low-temperature conditions has been preliminarily validated, the optimization and practical application of this device still face challenges such as insufficient understanding of material properties. This work addresses issues such as the unclear carrier dynamics mechanisms in GeSn alloy applications in infrared photonics. A theoretical model integrating band parameters, non-equilibrium carrier transport, and radiative recombination is proposed to systematically investigate the mechanism by which thermal excitation and phonon-assisted processes influence the direct-band spontaneous emission in GeSn alloys under variable temperature conditions. The results indicate that the carrier transfer process between the ΓCBM and LCBM energy bands of GeSn alloy exhibits significant composition dependence: for low-Sn-content GeSn alloy with Sn content below 10%, temperature-induced LCBM→ΓCBM electron transfer dominates, leading to an increase in direct band emission efficiency with temperature rising, whereas in high-Sn-content GeSn alloys with Sn content between 10% and 20%, the ΓCBM→LCBM electron escape process is more pronounced, resulting in a decrease in direct band emission efficiency with the increase of temperature. A modified Arrhenius model of the carrier dynamics competition further indicates that thermal excitation and phonon scattering synergistically regulate electron transfer between ΓCBM and LCBM. The analysis based on the modified Arrhenius model further indicates that both thermal excitation and phonon-assisted processes promote the injection and escape of electrons in the ΓCBM valley, acting as key factors in modulating the radiative recombination efficiency at the direct bandgap of GeSn alloy. The red shift of the peak position in the spontaneous emission spectrum of GeSn alloy is mainly due to the bandgap contraction effect; At the same time, phonon-assisted processes reduce the dispersion of carrier energy distribution, leading to a pronounced narrowing effect in the direct band emission spectrum. The quantitative findings further elucidate the mechanism by which thermal excitation and phonon-assisted processes influence the direct bandgap luminescence of GeSn alloy, providing theoretical guidance for the performance regulation of infrared optoelectronic devices.
-
Keywords:
- GeSn alloys /
- thermal excitation /
- phonon assisted /
- direct band emission
-
图 1 热激发模型下, 注入载流子浓度为1×1018 cm–3时, GeSn合金的直接带隙(ΓCBM→ΓVBM)变温自发发射光谱 (a) Sn组分为5%; (b) Sn组分为15%
Fig. 1. Temperature-dependent spontaneous emission spectra of GeSn alloys under thermal excitation model at an injected carrier concentration of 1×1018 cm–3: (a) Sn content of 5%; (b) Sn content of 15%.
图 2 GeSn合金直接带隙发光强度随组分与温度变化的三维相图 (a) 低组分(x = 0—10%)热激发模型; (b) 低组分(x = 0—10%)声子辅助模型; (c) 高组分(x = 10%—20%)热激发模型; (d) 高组分(x = 10%—20%)声子辅助模型
Fig. 2. Three-dimensional maps of direct bandgap emission intensity of GeSn alloys as a function of Sn content and temperature: (a) Thermal excitation model at low Sn content (x = 0%–10%); (b) phonon-assisted model at low Sn content (x = 0%–10%); (c) thermal excitation model at high Sn content (x = 10%–20%); (d) phonon-assisted model at high Sn content (x = 10%–20%).
图 3 100 K时不同Sn组分下的声子辅助模型辐射复合示意图 (a) Sn组分为5%; (b) Sn组分为15%
Fig. 3. Schematic diagram of phonon-assisted radiative recombination under different Sn compositions at 100 K: (a) 5% Sn composition; (b) 15% Sn composition.
图 4 利用改进型Arrhenius模型拟合的GeSn合金变温自发发射谱积分强度图 (a) 组分为5%, 热激发模型; (b) 组分为5%, 声子辅助模型; (c) 组分为15%, 热激发模型; (d) 组分为15%, 声子辅助模型
Fig. 4. Temperature-dependent integrated spontaneous emission intensity of GeSn alloys fitted with the modified Arrhenius model: (a) 5% Sn, thermal excitation model; (b) 5% Sn, phonon-assisted model; (c) 15% Sn, thermal excitation model; (d) 15% Sn, phonon-assisted model.
图 5 GeSn 材料在不同Sn含量下, 分别考虑热激发模型与声子辅助模型时提取的热激活能(Ea)随组分变化的趋势对比图
Fig. 5. Sn content dependence of extracted thermal activation energy (Ea) in GeSn alloys under thermal excitation and phonon-assisted models.
图 6 GeSn合金自发发射谱半高宽随温度的变化趋势 (a) 热激发模型; (b) 声子辅助模型
Fig. 6. Temperature dependence of the full width at half maximum (FWHM) of spontaneous emission spectra of GeSn alloys: (a) Thermal excitation model; (b) phonon-assisted model.
图 7 GeSn合金自发发射谱峰位随温度的变化趋势 (a) 热激发模型; (b) 声子辅助模型
Fig. 7. Variation of emission peak energy with temperature for GeSn alloys under (a) thermal excitation and (b) phonon-assisted models.
-
[1] Chang G E, Yu S Q, Liu J, Cheng H H, Soref R A, Sun G 2022 IEEE J. Sel. Topics Quantum Electron. 28 3800611
[2] Giunto A, Morral A F I 2024 Appl. Phys. Rev. 11 41333
Google Scholar
[3] An S, Park H, Kim M 2023 J. Mater. Chem. C 11 2430
Google Scholar
[4] Miao Y H, Wang G L, Kong Z Z, Xu B Q, Zhao X W, Luo X, Lin H X, Dong Y, Lu B, Dong L P, Zhou J R, Liu J B, Radamson H H 2021 Nanomaterials 11 2556
Google Scholar
[5] Reboud V, Gassenq A, Pauc N, Aubin J, Milord L, Thai Q M, Bertrand M, Guilloy K, Rouchon D, Rothman J, Zabel T, Armand P F, Sigg H, Chelnokov A, Hartmann J M, Calvo V 2017 Appl. Phys. Lett. 111 92101
Google Scholar
[6] Ghosh S, Bansal R, Sun G, Soref R A, Cheng H H, Chang G E 2022 Sensors 22 3978
Google Scholar
[7] Huang Y P, Wu B R, Ghosh S, Jheng Y T, Ho Y L, Wu Y J, Wisessint A, Kim M, Chang G E 2024 Opt. Express 32 39560
Google Scholar
[8] Qian L, Fan W J, Tan C S, Zhang D H 2017 Opt. Mater. Express 7 800
Google Scholar
[9] Liu J F 2014 Photonics 1 162
Google Scholar
[10] Sun X, Liu J, Kimerling L C, Michel J 2009 Appl. Phys. Lett. 95 011911
Google Scholar
[11] Du W, Ghetmiri S A, Conley B R, Mosleh A, Nazzal A, Soref R A, Sun G, Tolle J, Margetis J, Naseem H A, Yu S Q 2014 Appl. Phys. Lett. 105 51104
Google Scholar
[12] Huang S H, Zheng Q Q, Xie W M, Lin J Y, Huang W, Li C, Qi D F 2018 J. Phys. : Condens. Matter. 30 465701
Google Scholar
[13] Ryu M Y, Harris T R, Yeo Y K, Beeler R T, Kouvetakis J 2013 Appl. Phys. Lett. 102 171908
Google Scholar
[14] Julsgaard B, Von D, Tidemand L P, Pedersen C, Ikonic Z, Buca D 2020 Photonics Res. 8 788
Google Scholar
[15] Menéndez J, Poweleit C D, Tilton S E 2020 Phys. Rev. B 101 195204
Google Scholar
[16] Wu S S, Huang S H, Qian J H, Huang W, Lin G Y, Cheng S Y, Li C 2025 J. Phys. D: Appl. Phys. 58 135308
Google Scholar
[17] Viña L, Logothetidis S, Cardona M 1984 Phys. Rev. B 30 1979
Google Scholar
[18] Bertrand M, Thai Q, Chrétien J, Pauc N, Aubin J, Milord L, Gassenq A, Hartmann J, Chelnokov A, Calvo V, Reboud V 2019 Annal. Phys. 531 1800396
Google Scholar
[19] Hong H Y, Zhang L, Qian K, An Y Y, Li C, Li J, Chen S Y, Huang W, Wang J Y, Zhang S H 2021 Opt. Express 29 441
Google Scholar
[20] 黄诗浩, 李佳鹏, 李海林, 卢旭星, 孙钦钦, 谢灯 2025 74 36101
Google Scholar
Huang S H, Li J P, Li H L, Lu X X, Sun Q Q, Xie D 2025 Acta Phys. Sin. 74 36101
Google Scholar
[21] Huang S H, Li C, Chen C Z, Zheng Y Y, Lai H K, Chen S Y 2012 Acta Phys. Sin. 61 36202 (in Chinese) [黄诗浩, 李成, 陈城钊, 郑元宇, 赖虹凯, 陈松岩 2012 61 36202]
Google Scholar
Huang S H, Li C, Chen C Z, Zheng Y Y, Lai H K, Chen S Y 2012 Acta Phys. Sin. 61 36202 (in Chinese)
Google Scholar
[22] Chuang S L 2009 Physics of Photonic Devices 2nd ed (Hoboken, N. J: John Wiley & Sons) p347
[23] Wirths S, Geiger R, Von Den Driesch N, Mussler G, Stoica T, Mantl S, Ikonic Z, Luysberg M, Chiussi S, Hartmann J M, Sigg H, Faist J, Buca D, Grützmacher D 2015 Nat. Photonics 9 88
Google Scholar
[24] Ghosh S, Sun G, Yu S Q, Chang G E 2025 IEEE J. Select. Topics Quantum Electron. 31 1
[25] Huang B J, Chang C Y, Hsieh Y D, Soref R A, Sun G, Cheng H H, Chang G E 2019 ACS Photonics 6 1931
Google Scholar
[26] Huang Q X, Liu X Q, Zheng J, Yang Y Z, Zhang D D, Pang Y Q, Cui J L, Liu Z, Zuo Y H, Cheng B W 2023 J. Lumin. 255 119623
Google Scholar
[27] Fang Y T, Wang L, Sun Q L, Lu T P, Deng Z, Ma Z G, Jiang Y, Jia H Q, Wang W X, Zhou J M, Chen H 2015 Sci. Rep. 5 12718
Google Scholar
下载:
计量
- 文章访问数: 361
- PDF下载量: 10
- 被引次数: 0
