Confirmation of transition-bound excitons in GaN-based MQW LDs at room temperature using AC differential capacitance response spectroscopy

Abstract

Excitons play an important role in semiconductor physics, whereas their electrical characteristics have rarely been explored. Here, AC differential capacitance response spectroscopy is applied to GaN-based multi-quantum-well (MQW) laser diodes (LDs) to investigate the transition-bound excitons. The capacitance response aligns with a modified rate equation, exhibiting negative activation energy, attributed to a sub-stable transition-bound state. Temperature dependent measurements yield binding energies of the transition-bound state consistent with weakly confined excitons in III–V quantum structures. These results confirm transition-bound excitons under continuous electrical excitation. As a comparison, the differential capacitance response of GaAs-based MQW LDs has shown that there is no negative activation energy, which further confirms the transition-bound excitons in GaN-based MQW LDs at room temperature. In addition, simulations of GaN-based MQW LDs’ capacitance response match experimental results well.

Keywords

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References

[1] Zuo X, Fan Z Y, Zhu H B, et al. Entangling two exciton modes using exciton optomechanics. Physical review A, 2024, 1105053502. J]

[2] Lee H, Kim Y B, Ryu J W, et al. Recent progress of exciton transport in two-dimensional semiconductors. Nano convergence, 2023, 1015773. J]

[3] Esteve-Paredes J J, García-Blázquez M A, Uría-Álvarez A J, et al. Excitons in nonlinear optical responses: shift current in MoS₂ and GeS monolayers. NPJ computational materials, 2025, 1111323. J]

[4] Rahman E, Nojeh A. Semiconductor thermionics for next generation solar cells: photon enhanced or pure thermionic. Nature communications, 2021, 12146224627. J]

[5] Lu K F, Zhang J Y. High-power narrow linewidth tunable single-frequency fiber laser. Journal of optoelectronics-laser, 2025, 364369374[J]

[6] Qian W, Qi P, Dai Y, et al. Transient dynamics and long-range transport of 2D exciton with managed potential disorder and phonon scattering. NPJ 2D materials and applications, 2024, 817887. J]

[7] Fang H, Lin Q, Zhang Y, et al. Localization and interaction of interlayer excitons in MoSe₂/WSe₂ heterobilayers. Nature communications, 2023, 14169106917. J]

[8] Ha My Dang N, Bouteyre P, Trippé-Allard G, et al. Nanoimprinted exciton-polaritons metasurfaces: cost-effective, large-scale, high homogeneity, and room temperature operation. Optical materials express, 2024, 14616551669. J]

[9] Salikhov K M. New approach to the formation of a Bose–Einstein condensate. Applied magnetic resonance, 2025, 561213228. J]

[10] Baghdasaryan D A, Harutyunyan V A, Kazaryan E M, et al. Possibility of exciton Bose–Einstein condensation in CdSe nanoplatelets. Nanomaterials, 2023, 13192734. J]

[11] Dawson P, Duggan G, Ralph H I, et al. Free excitons in room-temperature photoluminescence of GaAs-Al_xGa_1-xAs multiple quantum wells. Physical review B, 1983, 281273817383. J]

[12] Fujiwara K, Tsukada N, Nakayama T. Observation of free excitons in room-temperature photoluminescence of GaAs/AlGaAs single quantum wells. Applied physics letters, 1988, 538675677. J]

[13] Tang Z K, Wong G K L, Yu P, et al. Room temperature ultraviolet laser emission from self-assembled ZnO microcrystallite thin flms. Applied physics letters, 1998, 722532703272. J]

[14] Sarma S D, Wang D W. Many-body renormalization of semiconductor quantum wire excitons: absorption, gain, binding, and unbinding. Physical review letters, 2000, 84920102013. J]

[15] Noriyasu M, Fujiwara K. Excitonic electroluminescence at room temperature in an (In, Ga)As multiple-quantum-well diode. Applied physics letters, 2010, 973031103. J]

[16] Feng L, Wang S, Li Y, et al. Exciton recombination in lasing contributing an opposite abrupt change of the electrical behavior near threshold between GaN- and GaAs-multi-quantum-well laser diodes. Journal of physics D: applied physics, 2018, 519095102. J]

[17] Meron O, Arieli U, Bahar E, et al. Shaping exciton polarization dynamics in 2D semiconductors by tailored ultrafast pulses. Light: science & applications, 2025, 148018[J]

[18] Zhang W, Huang W, Wu B, et al. Excitonic effect in MOFs-mediated photocatalysis: phenomenon, characterization techniques and regulation strategies. Coordination chemistry reviews, 2023, 4919215235. J]

[19] Bhunia A, Bansal K, Henini M, et al. Negative activation energy and dielectric signatures of excitons and excitonic Mott transitions in quantum confined laser structures. Journal of applied physics, 2016, 12014144304. J]

[20] Bansali K, Henini M, Alshammari M S, et al. Dynamics of electronic transitions and frequency dependence of negative capacitance in semiconductor diodes under high forward bias. Applied physics letters, 2014, 10512123503. J]

[21] Wu T H, Cheng H Y, Lai W C, et al. Ultrafast carrier dynamics and layer-dependent carrier recombination rate in InSe. Nanoscale, 2023, 15731693176. J]

[22] Ghahremanirad E, Almora O, Suresh S, et al. Beyond protocols: understanding the electrical behavior of perovskite solar cells by impedance spectroscopy. Advanced energy materials, 2023, 13302204370. J]

[23] Laidler K J. The development of the Arrhenius equation. Journal of chemical education, 1984, 616494198. J]

[24] Fregolent M, Boito M, Disaró M, et al. Negative activation energy of gate reliability in Schottky-Gate p-GaN HEMTs: combined gate leakage current modeling and spectral electroluminescence investigation. IEEE journal of the electron devices society, 2024, 121703709. J]

[25] Böer K W, Pohl U W. Semiconductor physics, 20232nd ed.BerlinSpringer Nature580627. M]

[26] Chow W W, Choquette K D, Crawford M H, et al. Design, fabrication, and performance of infrared and visible vertical-cavity surface-emitting lasers. IEEE journal of quantum electronics, 1997, 331018101824. J]

[27] Yariv A. Quantum electronics, 19893rd ed.New YorkJohn Wiley & Sons402435[M]

[28] Bigenwald P, Lefebvre P, Bretagnon T, et al. Confined excitons in GaN-AlGaN quantum wells. Physica status solidi (b), 1999, 2161371374. J]

[29] Nakamura S, Senoh M, Nagahama S, et al. High-power, long-lifetime InGaN/GaN/AlGaN-based laser diodes grown on pure GaN substrates. Japanese journal of applied physics, 1998, 373BL309L312. J]

[30] Nakamura S. The roles of structural imperfections in InGaN-based blue light-emitting diodes and laser diodes. Science, 1998, 2815379956961. J]

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