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1Stimulated emission in HgCdTe heterostructures with quantum wells in 3 - 5 ^m spectral window
A. Dubinov1*, K. Kudryavtsev1, M. Fadeev1, V. Utochkin1, A. Razova1, A. Yantser1, K. Mazhukina1, D. Shengurov1, N. Gusev1, N. Mikhailov2, S. Dvoretskii2, V. Rumyantsev1, S. Morozov1
1- Institute of Microstructure Physics RAS, Nizhny Novgorod, 603087, Russia 2- Institute of Semiconductor Physics RAS, Novosibirsk, 630090, Russia
Hg(Cd)Te/CdHgTe heterostructures with narrow quantum wells (QWs) are one of the promising materials for lasers in the mid-infrared range. The quasi-hyperbolic dispersion law of charge carriers provides a noticeable suppression of non-radiative Auger processes in such structures. Previously, stimulated emission (SE) was obtained in HgCdTe QWs in the wavelength range from 2 to 31 ^m [1,2].
In this work, we focus on the range of 3-5 ^m, a window of atmospheric transparency containing a large number of absorption lines of trace atmospheric gases. We study losses in waveguide HgCdTe heterostructures and balance the number of QW in the active region to achieve the best performance of a laser structure [3]. We show that non-threshold Auger processes may have a greater contribution to the overall recombination rate than expected before and then work out the optimal structure design by analysing the photoluminescence intensity dependence on temperature [4]. The results allowed us to achieve stimulated emission in the vicinity of 3.55 ^m approaching room temperature operation (290 K).
Using laser or explosive lithography and ion etching methods microdisk, microring and stripe-shaped optical cavities were formed from Hg(Cd)Te/CdHgTe QWs heterostructures. Etching was carried out with argon ions. Photoresist and metal masks (Al or Cr/V/Ni) were compared to figure out the best mask type. Finally, we demonstrate laser action under optical pumping in the temperature range attainable by Peltier cooling. However, in all mesa structures the maximum operating temperature Tmax decreases by an average of 30-40 K compared to Tmax of the original unprocessed structures. The Tmax drop is attributed to increase in the optical losses, which are negligible in the macroscopic samples providing SE. In addition, surface recombination and defects appearing after ion etching process are also believed to make an impact. However, laser emission in best mesastructures persists up to 230 K and the integral power of optical pumping for a 50 ^m microdisk is estimated to be about 1 W, which is achievable for commercial semiconductor diode lasers. Thus, the results of the work pave the way to optically pumped converters operating in 3-5 ^m spectral window under thermoelectric cooling.
The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme No. 124050300055-9 (FFUF-2024-0045)).
[1] S.V. Morozov, V.V. Rumyantsev, M.S. Zholudev, et al, Coherent Emission in the Vicinity of 10 THz due to Auger-Suppressed Recombination of Dirac Fermions in HgCdTe Quantum Wells. ACS photonics 8 (12), 3526 (2021).
[2] A.A. Andronov, Yu.N. Nozdrin, A.V. Okomel'kov, A.A. Babenko, V.S. Varavin, D.G. Ikusov, R.N. Smirnov, Stimulated radiation of optically pumped CdxHgi-xTe-based heterostructures at room temperature. Semiconductors 42 (2), 179 (2008).
[3] M.A. Fadeev, A.A. Dubinov, A.A. Razova, et al, Balancing the Number of Quantum Wells in HgCdTe/CdHgTe Heterostructures for Mid-Infrared Lasing. Nanomaterials 12 (24) (2022).
[4] K.E. Kudryavtsev, A.A. Yantser, M.A. Fadeev, et al, Quantifying non-threshold Auger-recombination processes in mid-wavelength infrared range HgCdTe quantum wells. Applied Physics Letters 123 (18) (2023).
