Anion vacancies as a source of persistent photoconductivity in II-VI and chalcopyrite semiconductors

Abstract

Using first-principles electronic structure calculations we identify the anion vacancies in II-VI and chalcopyrite Cu-III-VI2 semiconductors as a class of intrinsic defects that can exhibit metastable behavior. Specifically, we predict persistent electron photoconductivity (n-type PPC) caused by the oxygen vacancy VO in n-ZnO, and persistent hole photoconductivity (p-type PPC) caused by the Se vacancy VSe in p-CuInSe2 and p-CuGaSe2. We find that VSe in the chalcopyrite materials is amphoteric having two "negative-U" like transitions, i.e. a double-donor transition e(2+/0) close to the valence band and a double-acceptor transition e(0/2-) closer to the conduction band. We introduce a classification scheme that distinguishes two types of defects (e.g., donors): type-alpha, which have a defect-localized-state (DLS) in the gap, and type-beta, which have a resonant DLS within the host bands (e.g., conduction band). In the latter case, the introduced carriers (e.g., electrons) relax to the band edge where they can occupy a perturbed-host-state (PHS). Type alpha is non-conducting, whereas type beta is conducting. We identify the neutral anion vacancy as type-alpha and the doubly positively charged vacancy as type-beta. We suggest that illumination changes the charge state of the anion vacancy and leads to a crossover between alpha- and beta-type behavior, resulting in metastability and PPC. In CuInSe2, the metastable behavior of VSe is carried over to the (VSe-VCu) complex, which we identify as the physical origin of PPC observed experimentally. We explain previous puzzling experimental results in ZnO and CuInSe2 in the light of this model.

submitted to Phys. Rev. B

References in corpus (3)

• All-electron self-consistent GW approximation: Application to Si, MnO, and NiO
• Diluted II-VI Oxide Semiconductors with Multiple Band Gaps
• All-electron GW calculation based on the LAPW method: application to wurtzite ZnO

Cited by in corpus (31)

• Oxygen vacancies: The origin of n-type conductivity in ZnO
• Rich variety of defects in ZnO via an attractive interaction between O-vacancies and Zn-interstitials
• ALD grown zinc oxide with controllable electrical properties
• Manybody GW calculation of the oxygen vacancy in ZnO
• Functionality-directed Screening of Pb-free Hybrid Organic-inorganic Perovskites with Desired Intrinsic Photovoltaic Functionalities
• Band widths and gaps from the Tran-Blaha functional : Comparison with many-body perturbation theory
• Identifying the ground state structures of point defects in solids
• Ferromagnetism and spin polarized charge carriers in In${}_2$O${}_3$ thin films
• Electrical conduction processes in ZnO in a wide temperature range 20--500 K
• Structural Stability and Defect Energetics of ZnO from Diffusion Quantum Monte Carlo
• Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition
• Large and Persistent Photoconductivity due to Hole-Hole Correlation in CdS
• Intrinsic deep hole trap levels in $C{u}_{2}O$ with self-consistent repulsive Coulomb energy
• Experimental and theoretical study of stable and metastable phases in sputtered CuInS${}_2$
• Defect physics of BaCuChF (Ch=S, Se, Te) p-type transparent conductors
• Oxygen Vacancies on SrO-terminated SrTiO3(001) Surfaces studied by Scanning Tunneling Spectroscopy
• Fluorine doping: A feasible solution to enhancing the conductivity of high-resistance wide bandgap Mg0.51Zn0.49O active components
• Ultrafast generation and decay of a surface metal
• Oxygen vacancy and EC - 1 eV electron trap in ZnO
• Tail-states induced semiconductor-toconductor like transition under sub-bandgap light excitation in the zinc-tin-oxide photothinfilm transistors
• Sources of n-type conductivity in GaInO3
• Tellurium vacancy in cadmium telluride revisited: size effects in the electronic properties
• Persistent ion beam induced conductivity in zinc oxide nanowires
• Linear-response calculation of the effective Coulomb interaction between closed-shell localized electrons: Cu, Zn, and ZnO
• Defect Level Switching for Highly-Nonlinear and Hysteretic Electronic Devices
• Machine Learning Prediction of Charged Defect Formation Energies from Crystal Structures
• Identifying Split Vacancy Defects with Machine-Learned Foundation Models and Electrostatics
• Modeling Defect-Level Switching for Highly-Nonlinear and Hysteretic Electronic Devices
• Swift Heavy Ion Irradiation Induced Modifications in Structural, Microstructural, Electrical and Magnetic Properties of Mn Doped $Sn{O}_2$ Thin Films
• Accelerating point defect simulations using data-driven and machine learning approaches
• Light-driven permanent transition from insulator to conductor in Ga2O3