Doping Limits of Phosphorus, Arsenic, and Antimony in CdTe

Chatratin, Intuon; Dou, Baoying; Wei, Su‐Huai; Janotti, Anderson

doi:10.1021/acs.jpclett.2c03233

Cited by 11 publications

(3 citation statements)

References 39 publications

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“…The self-compensation process in group-V doped CdTe has been proposed by the metastable AX center from previous theoretical studies; however, the AX configuration was not supported in this experimental XFH study. In a recent theoretical study on the supercell size and effects of spin-orbit coupling, the AX center was predicted to be unstable . Moreover, Cd interstitial (Cd i ) under Cd-rich composition can be considered as a potential donor defect for self-compensation.…”

Section: Results and Discussionmentioning

confidence: 99%

Direct Observation of Group-V Dopant Substitutional Defects in CdTe Single Crystals

et al. 2023

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Point defect chemistry strongly affects the fundamental properties of materials and has a decisive impact on device performance. The Group-V dopant is prominent acceptor species with high hole concentration in CdTe; however, its local atomic structure is still not clear owing to difficulties in definitive measurements and discrepancies between experimental observations and theoretical models. Herein, we report on direct observation of the local structure for the As dopant in CdTe single crystals by the X-ray fluorescence holography (XFH) technique, which is a powerful tool to visualize three-dimensional atomic configurations around a specific element. The XFH result shows the As substituting on both Cd (As Cd ) and Te (As Te ) sites. Although As Te has been well known as a shallow acceptor, As Cd has not attracted much attention and been discussed so far. Our results provide new insights into point defects by expanding the experimental XFH study in combination with theoretical first-principles studies in II−VI semiconductors.

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Section: Results and Discussionmentioning

confidence: 99%

Direct Observation of Group-V Dopant Substitutional Defects in CdTe Single Crystals

et al. 2023

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“…We note that a recent study shows that charge transition levels in CdTe converge slowly as 1=L, where L is the size of the supercell. 57 The slow convergence primarily concerns shallow defects of extended wavefunctions. Since the defect-defect interaction scales inversely with the dielectric constant, we expect such a finite-size effect to diminish for defects in Hg 0:75 Cd 0:25 Te.…”

Section: Defect Computationsmentioning

confidence: 99%

Native point defects in HgCdTe infrared detector material: Identifying deep centers from first principles

Chen,

Rignanese,

Liu

et al. 2024

Journal of Applied Physics

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We investigate the native point defects in the long-wavelength infrared (LWIR) detector material Hg0.75Cd0.25Te using a dielectric-dependent hybrid density functional combined with spin–orbit coupling. Characterizing these point defects is essential as they are responsible for intrinsic doping and nonradiative recombination centers in the detector material. The dielectric-dependent hybrid functional allows for an accurate description of the bandgap (Eg) for Hg1−xCdxTe (MCT) over the entire compositional range, a level of accuracy challenging with standard hybrid functionals. Our comprehensive examination of the native point defects confirms that cation vacancies VHg(Cd) are the primary sources of p-type conductivity in the LWIR material given their low defect formation energies and the presence of a shallow acceptor level (−/0) near the valence-band maximum. In addition to the shallow acceptor level, the cation vacancies exhibit a deep charge transition level (2−/−) situated near the midgap, characteristic of nonradiative recombination centers. Our results indicate that Hg interstitial could also be a deep center in the LWIR MCT through a metastable configuration under the Hg-rich growth conditions. While an isolated Te antisite does not show deep levels, the formation of VHg–TeHg defect complex introduces a deep acceptor level within the bandgap.

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“…[19,4,29,17] Defects introduced by As were also studied, specifically AX centers. [65,68] As-introduced defect clusters were identified with atom probe tomography. [69] As substituting on both Te and Cd was imaged by X-ray fluorescence holography.…”

Section: Compensation Reduces V Rad Oc In As-doped Solar Cellsmentioning

confidence: 99%

Why Increased CdSeTe Charge Carrier Lifetimes and Radiative Efficiencies did not Result in Voltage Boost for CdTe Solar Cells

Kuciauskas

Nardone

Bothwell

et al. 2023

Advanced Energy Materials

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After a focused effort over the last decade, order‐of‐magnitude improvements in doping and electro‐optical characteristics (radiative efficiency, carrier lifetime, and passivation) have been reported for polycrystalline CdSeTe solar cells. Surprisingly, this did not result in higher solar cell voltages regardless of device contacting layers, absorber grading profiles, and other changes in device architecture. From detailed evaluation of radiative emission and carrier dynamics in CdSeTe heterostructures and devices, it is shown that the complexity introduced to the absorber to achieve lifetime and passivation metrics resulted in charge carrier trapping, which now negatively affects CdSeTe absorbers. It is found that the defects with activation energy Ea ≈ 0.14‐0.22 eV dominate radiative emission and carrier dynamics in undoped CdSeTe, and electronic potential fluctuations with the amplitude γ ≈ 45–60 meV are present in As‐doped CdSeTe/CdTe. Because of potential fluctuations, radiative voltage is reduced by ≈ −100 mV, to = 1020‐1050 mV (for 1.4 eV bandgap). For record‐efficiency solar cells with VOC ≥900 mV, radiative and nonradiative recombination voltage losses are comparable, and future research needs to focus on reducing dopant compensation which causes potential fluctuations. This represents a paradigm shift for CdTe solar cells, with non‐radiative bulk recombination no longer representing a dominant voltage loss pathway.

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Doping Limits of Phosphorus, Arsenic, and Antimony in CdTe

Cited by 11 publications

References 39 publications

Direct Observation of Group-V Dopant Substitutional Defects in CdTe Single Crystals

Direct Observation of Group-V Dopant Substitutional Defects in CdTe Single Crystals

Native point defects in HgCdTe infrared detector material: Identifying deep centers from first principles

Why Increased CdSeTe Charge Carrier Lifetimes and Radiative Efficiencies did not Result in Voltage Boost for CdTe Solar Cells

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