DLTS evaluation of nonexponential transients of defect levels in cuprous oxide (Cu2O)

Papadimitriou, L.

doi:10.1016/0038-1101(93)90098-b

Cited by 19 publications

(17 citation statements)

References 20 publications

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“…Although the p-type conduction properties of Cu 2 O have been studied extensively for decades, [15][16][17][18][19] the exact nature of the hole states found in the forbidden energy gap of Cu 2 O has been a source of much controversy, with acceptorlike states being reported in the range 0.12-0.70 eV. [20][21][22][23][24][25][26][27] Deep level transient spectroscopy ͑DLTS͒ has shown the presence of hole traps 0.40-0.55 eV above the top of the valence band maximum ͑VBM͒. 26,28 These hole traps have been attributed to structural anomalies such as CuO "islands."…”

Section: Introductionmentioning

confidence: 99%

“…[20][21][22][23][24][25][26][27] Deep level transient spectroscopy ͑DLTS͒ has shown the presence of hole traps 0.40-0.55 eV above the top of the valence band maximum ͑VBM͒. 26,28 These hole traps have been attributed to structural anomalies such as CuO "islands." 26 Similar conclusions were reached regarding the acceptor levels in DLTS study of Cd-doped Cu 2 O.…”

Section: Introductionmentioning

confidence: 99%

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Modeling the polaronic nature of p-type defects in Cu2O: The failure of GGA and GGA+U

Scanlon

Morgan

Watson

2009

The Journal of Chemical Physics

138

113

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The exact nature of the hole traps reported deep in the band gap of Cu(2)O has been a topic of vigorous debate, with copper vacancies and oxygen interstitials both having been proposed as the relevant defects. In this article, the electronic structure of acceptor-forming defects in Cu(2)O, namely, copper vacancies and oxygen interstitials, is investigated using generalized gradient approximation (GGA) and GGA corrected for on-site Coulombic interactions (GGA+U). GGA produces notionally semimetallic defect complexes, which is not consistent with the experimentally known polaronic nature of conduction in Cu(2)O. GGA+U also predicts a semimetallic defect complex for the "simple" copper vacancy but predicts the "split" vacancy and both oxygen interstitials are characterized by localized polarons, with distinct single particle levels found in the band gap. For both methods, however, the positions of calculated transition levels are inconsistent with experimental ionization levels. Hence neither GGA nor GGA+U are successful in modeling p-type defects in Cu(2)O.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling the polaronic nature of p-type defects in Cu2O: The failure of GGA and GGA+U

Scanlon

Morgan

Watson

2009

The Journal of Chemical Physics

138

113

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“…Within this composition window, we obtain predicted band gap energies between 1.4 (x Cd = y Se = 0.2) and 2.5 eV (x Mg = 0.2) from the values given in Table II, compared to the 2.1 eV room temperature gap of Cu 2 O [50]. Whereas the binary oxide Cu 2 O is always p-type conducting within a narrow window p = 10 14 − 10 16 cm −3 [25,39,51] we find the alloying approach allows a much better control of the electrical properties. Due to the pronounced dopantdefect interaction, alloying of S and Se increases the ptype doping, up to the 10 18 cm −3 range for y Se > 0.02 (Fig.…”

Section: Discussionmentioning

confidence: 92%

Composition Dependence of the Band Gap and Doping inCu2O-Based Alloys as Predicted by an Extension of the Dilute-Defect Model

2014

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Tuning the opto-electronic properties through alloying is essential for semiconductor technology. Currently, mostly isovalent and isostructural alloys are used (e.g., group-IV and III-V), but a vast and unexplored space of novel functional materials is conceivable when considering more complex alloys by mixing aliovalent and heterostructural constituents. The real challenge lies in the quantitative property prediction for such complex alloys to guide their experimental exploration. We developed an approach to predict compositional dependence of both band-structure and electrical properties from ab-initio calculations by extending conventional dilute defect model to higher (alloy) concentrations. Considering alloying of aliovalent (Mg, Zn, Cd) cations and isovalent anions (S, Se) into Cu2O, we predict tunability of band-gap energies and doping levels over a wide range, including the type conversion from p-to n-type. Initial synthesis and characterization of Zn and Se substituted Cu2O support the defect model, suggesting these alloys as promising novel oxide semiconductor materials. Cu-poor (Cu 2 O/CuO)Cu-rich (Cu 2 O/Cu)

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“…However, other studies suggested that this effect could better be interpreted as a correction factor on Gaussian distributions. 17 Batovski and Hardalov 18 pointed out that the distribution function could be more complicated and asymmetric in considering the spin degeneracy and lattice relaxation during the carrier capture and emission processes. They suggested an inverse theory to transform the thermal spectrum directly into a defect energy distribution spectrum.…”

Section: Introductionmentioning

confidence: 99%

Broadening effects and ergodicity in deep level photothermal spectroscopy of defect states in semi-insulating GaAs: A combined temperature-, pulse-rate-, and time-domain study of defect state kinetics

Xia

Mandelis

2009

Journal of Applied Physics

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The technique of deep level photothermal spectroscopy ͑DLPTS͒ is extended to the low temperature region in order to cover several defect states in semi-insulating GaAs. Measurements are taken at three different modes, temperature-scanned, pulse-rate-scanned, and time-scanned DLPTS. It is demonstrated that each mode provides unique information about the defect configuration, and the combination of the different modes offers a powerful tool for DLPTS studies of physical optoelectronic processes in SI-GaAs. The nonexponentiality/broadening of experimental data is extensively studied using the two prevalent broadening theories: the stretched exponential and the Gaussian distribution of activation energies. A hierarchical carrier emission model has been proposed for the stretched exponential behavior. Simulations indicate that the two broadening theories exhibit roughly similar broadening effects and good fits to the experimental data. The origin of this similarity indicates an ergodic equivalence of random energy distribution and the constrained hierarchical emission process.

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DLTS evaluation of nonexponential transients of defect levels in cuprous oxide (Cu2O)

Cited by 19 publications

References 20 publications

Modeling the polaronic nature of p-type defects in Cu2O: The failure of GGA and GGA+U

Modeling the polaronic nature of p-type defects in Cu2O: The failure of GGA and GGA+U

Composition Dependence of the Band Gap and Doping inCu2O-Based Alloys as Predicted by an Extension of the Dilute-Defect Model

Broadening effects and ergodicity in deep level photothermal spectroscopy of defect states in semi-insulating GaAs: A combined temperature-, pulse-rate-, and time-domain study of defect state kinetics

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