Competition between deep impurity and dopant behavior of Mg in GaN Schottky diodes

Schmeits, M.; Nguyen, Ngoc Duy; Germain, Marianne

doi:10.1063/1.1339208

Cited by 18 publications

(14 citation statements)

References 25 publications

(27 reference statements)

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“…[108][109][110][111][112][113][114]. In general, the Mg acceptor level positions determined from AS are qualitatively similar to those calculated from Hall effect/conductivity measurements.…”

Section: Mg In Iii-nitridessupporting

confidence: 71%

Deep traps in GaN-based structures as affecting the performance of GaN devices

Polyakov

Lee

2015

Materials Science and Engineering: R: Reports

205

177

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Section: Mg In Iii-nitridessupporting

confidence: 71%

Deep traps in GaN-based structures as affecting the performance of GaN devices

Polyakov

Lee

2015

Materials Science and Engineering: R: Reports

205

177

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“…It defines the position of the various energy levels with respect to a common zero reference level. Defects states either of donor or acceptor type can eventually be included [25], but will not be considered farther in this work. The electrical potential ψ obeys Poisson's equation…”

Section: Basic Formalismmentioning

confidence: 99%

Numerical simulation of impedance and admittance of OLEDs

Nguyen

Schmeits

2006

Physica Status Solidi (a)

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The electrical characteristics of organic light-emitting devices are calculated for the dc and ac regimes by numerically solving the basic semiconductor equations under steady-state and small-signal conditions. For a given structure, the dc and ac electric potential and electric field, the electron and hole concentrations, as well as the different components of the current density are obtained as function of the one-dimensional spatial coordinate. This approach allows a detailed microscopic description of the dependencies of these quantities on the applied steady-state voltage V 0 and the frequency of the modulating voltage. The final output consists in the frequency-dependent complex admittance and impedance of the device, the real and imaginary parts of which are the experimentally-available data. As a typical example, we show the results for a two-layer structure where α-NPD is the hole-transporting material and Alq 3 the electron-transporting material. The anode is made of ITO and Al/LiF composes the cathode. The admittance and impedance curves, yielded by the numerical simulation as functions of the modulation frequency, are fitted by an equivalent electrical circuit, the elements of which are resistances and capacitances. The number of components depends on the structure composition and on the applied steady-state voltage. We show that each element can be associated with a particular region of the device. This allows to correlate the dependence of each feature of the admittance and impedance curves with one or several parameters describing the material system. Such an analysis can be useful for the inverse approach, where, starting from measurements of the electrical ac characteristics, the aim is to get information on the microscopic mechanisms which contribute to the electrical conduction of the device.

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“…Therefore, the hole response cannot reach its maximum amplitude and the total cutoff frequency is practically equal to the defect transition frequency f tA . 24 In the inset of Fig. 5 we show the same quantities, but for a low-temperature case, with Tϭ130 K. The response of the level A has moved to lower frequencies, by about 3 decades.…”

Section: Microscopic Description Of the Junctionmentioning

confidence: 86%

“…This is a situation where the assumptions leading to the identification of the defect transition frequency f t with the thermal emission rate are not fulfilled. 18,24,30 Even when resistance effects do not exist, this leads to an expression of f t which is not simply equal to the hole emission rate e p , the difference in magnitude being of the order of a factor 10-50 and the temperature dependence not simply that of a thermally-activated process. Starting with an input value of (E tA ϪE V )ϭ210 meV, we have determined f tA by calculating the G/ peak position for a single and sufficiently short Schottky diode, such that series resistance effects play no role.…”

Section: Admittance Curves Of the Back To Back Connected Schottky mentioning

confidence: 99%

Thermal admittance spectroscopy of Mg-doped GaN Schottky diodes

Nguyen

Germain

Schmeits

et al. 2001

Journal of Applied Physics

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Thermal admittance spectroscopy measurements at temperatures ranging from room temperature to 90 K are performed on Schottky structures based on Mg-doped GaN layers grown by metalorganic vapor phase epitaxy on sapphire. The analysis of the experimental data is made by a detailed theoretical study of the steady-state and small-signal electrical characteristics of the structures. Numerical simulations are based on the solution of the basic semiconductor equations for the structure consisting of two Schottky diodes connected back to back by a conduction channel formed by the GaN layer. The description explicitly includes the Mg-related acceptor level, with its temperature-and position-dependent incomplete occupation state, leading to a dynamic exchange with the valence band. It fully reproduces the variations with temperature of the capacitancefrequency and conductance over frequency curves, allowing to give for all temperature ranges the origin of the various contributions to the junction capacitance and of the microscopic mechanisms responsible for the capacitance-frequency cutoff. Series resistance effects are shown to be dominant at temperatures above 230 K, whereas the Mg-related acceptor level governs the electrical behavior below 230 K. The existence of a second acceptor level with an activation energy of several tens of meV is revealed from the analysis of the characteristics at low temperature. An optimized fitting procedure based on the comparison of the electrical characteristics obtained from the numerical simulations to the experimental data allows one to determine the microscopic parameters describing the structure, among which the acceptor activation energies, thermal capture cross sections, concentrations, and the Schottky contact barrier heights are the most important ones. The obtained activation energy of the Mg-acceptor level of 210 meV is by a factor of 2 larger than that obtained from a classical Arrhenius plot, showing that a complete description of Mg-doped GaN junctions requires the correct treatment of the Mg level, acting as a dopant and as deep impurity, as well as the inclusion of series resistance effects.

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Competition between deep impurity and dopant behavior of Mg in GaN Schottky diodes

Cited by 18 publications

References 25 publications

Deep traps in GaN-based structures as affecting the performance of GaN devices

Deep traps in GaN-based structures as affecting the performance of GaN devices

Numerical simulation of impedance and admittance of OLEDs

Thermal admittance spectroscopy of Mg-doped GaN Schottky diodes

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