Dependence of the Melting Threshold of CdTe on the Wavelength and Pulse Lifetime of Laser Radiation
LEVYTSKYI Serhii1,*, CAO Zexiang2, KOBA Alexander3, KOBA Maria3
1 V. E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine, Kyiv 03028, Ukraine 2 Institute of Physics and Technology, National Technical University of Ukraine, Kyiv 03058, Ukraine 3 Faculty of State Security, Kyiv Institute of the National Guard of Ukraine, Kyiv 03028, Ukraine
Abstract: CdTe has a reasonably large atomic number of elements, a reasonably large photoelectric absorption cross-section, a suitable band gap, and thus a sufficiently high resistance. These properties are all advantages that make CdTe the primary material for nuclear detectors, and the detector can be operated at room temperature (without cooling). The melting threshold Ith of CdTe is affected by the wavelength λ of the laser light, which ranges from 300 nm to 800 nm, and the pulse lifetime τp, which ranges from 7 ns to 120 ns. During melting, the energy released by excess carriers is divided into three parts: (i) after excitation, (ii)during non-radiative scattering, and (iii)during non-radiative surface recombination, which together determine the depth of thermal penetration in the crystal and thus the melting threshold of CdTe in the surface region. The CdTe melting threshold is known to depend on the absorption coefficient α(λ) over a laser pulse lifetime range of 7 ns to 1 μs. At pulse lifetime greater than 1 μs, it depends on the reflection coefficient of the spectrum R(λ). Variations in the non-equilibrium excess carrier parameters found in this paper (lifetime, diffusion depth, and surface recombination rate) can affect the CdTe melting threshold by at least 25%. Since a large amount of work in this area of research has focused on the design of CdTe-based instruments that can be used for the detection and measurement of X-rays/gamma rays as well as for imaging. In this work, therefore, provides guidances for the development of CdTe-based semiconductor laser doping processes and the production of their diode structures.
列维茨基·谢尔盖, 曹泽祥, 柯巴·亚历山大, 柯巴·玛丽亚. 激光辐射波长和脉冲寿命对碲化镉熔化阈值的影响[J]. 材料导报, 2024, 38(7): 22120127-6.
LEVYTSKYI Serhii, CAO Zexiang, KOBA Alexander, KOBA Maria. Dependence of the Melting Threshold of CdTe on the Wavelength and Pulse Lifetime of Laser Radiation. Materials Reports, 2024, 38(7): 22120127-6.
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