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Updated: Jan 14, 2026

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope
Published on: May 28, 2016
Defect Engineering in CdS: Resolving p-Type Doping Controversies and Enabling Breakthrough n-Type Conductivity for
Yongcheng Zhu1,2, Zewen Xiao1,2
1Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.
Abstract:
Cadmium sulfide (CdS) serves as a vital wide-bandgap buffer/window layer in thin-film photovoltaics due to its superior optoelectronic properties. Despite its intrinsic weak n-type conductivity, persistent controversies surround the p-type doping feasibility. Concurrently, n-type enhancement in chemical bath deposition-grown CdS─where low carrier concentrations critically constrain device performance─faces persistent inconsistencies in dopant efficacy reports and insufficient exploration of alternatives. In this work, we resolve these challenges through systematic first-principles defect analysis, demonstrating that p-type doping remains fundamentally precluded by spontaneous VS-mediated compensation and deep acceptor levels in Group IB (CuCd, AgCd, AuCd) and Group VA (NS, PS, AsS) substitutions, compounded by interstitial donor compensation (Lii, Nai, Ki) dominating over substitutional acceptors (LiCd, NaCd, KCd) in Group IA systems. For n-type enhancement, transformative breakthroughs emerge where counterintuitive Cd-rich conditions maximize the Group IIIA efficacy (AlCd, GaCd, InCd), novel Group IIIB (ScCd, YCd, LaCd) substitutions achieve 5-6 order enhancement, and halogen doping (ClS, BrS, IS) under S-poor conditions yields a breakthrough 6-7 order conductivity improvement─surpassing all cation-based approaches. These defect-engineered strategies establish new paradigms for high-performance CdS window layers.
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