Hole Emission Research Articles

Efficient Perovskite Light Emitting Diodes Enabled by Mixed Ruddlesden–Popper (RP) Perovskite–Perovskite Planar Heterojunction between Hole Transport and Emission Layers

Efficient Perovskite Light Emitting Diodes Enabled by Mixed Ruddlesden–Popper (RP) Perovskite–Perovskite Planar Heterojunction between Hole Transport and Emission Layers

Comprehensive characterization of nitrogen-related defect states in β-Ga2O3 using quantitative optical and thermal defect spectroscopy methods

This study provides a comprehensive analysis of the dominant deep acceptor level in nitrogen-doped beta-phase gallium oxide (β-Ga2O3), elucidating and reconciling the hole emission features observed in deep-level optical spectroscopy (DLOS). The unique behavior of this defect, coupled with its small optical cross section, complicates trap concentration analysis using DLOS, which is essential for defect characterization in β-Ga2O3. A complex feature arises in DLOS results due to simultaneous electron emission to the conduction band and hole emission to the valence band from the same defect state, indicating the formation of two distinct atomic configurations and suggesting metastable defect characteristics. This study discusses the implications of this behavior on DLOS analysis and employs advanced spectroscopy techniques such as double-beam DLOS and optical isothermal measurements to address these complications. The double-beam DLOS method reveals a distinct hole emission process at EV+1.3 eV previously obscured in conventional DLOS. Optical isothermal measurements further characterize this energy level, appearing only in N-doped β-Ga2O3. This enables an estimate of the β-Ga2O3 hole effective mass by analyzing temperature-dependent carrier emission rates. This work highlights the impact of partial trap-filling behavior on DLOS analysis and identifies the presence of hole trapping and emission in β-Ga2O3. Although N-doping is ideal for creating semi-insulating material through the efficient compensation of free electrons, this study also reveals a significant hole emission and migration process within the weak electric fields of the Schottky diode depletion region.

Emission and capture characteristics of deep hole trap in n-GaN by optical deep level transient spectroscopy

Emission and capture characteristics of a deep hole trap (H1) in n-GaN Schottky barrier diodes (SBDs) have been investigated by optical deep level transient spectroscopy (ODLTS). Activation energy (E emi) and capture cross-section (σ p) of H1 are determined to be 0.75 eV and 4.67 × 10−15 cm2, respectively. Distribution of apparent trap concentration in space charge region is demonstrated. Temperature-enhanced emission process is revealed by decrease of emission time constant. Electric-field-boosted trap emission kinetics are analyzed by the Poole−Frenkel emission (PFE) model. In addition, H1 shows point defect capture properties and temperature-enhanced capture kinetics. Taking both hole capture and emission processes into account during laser beam incidence, H1 features a trap concentration of 2.67 × 1015 cm−3. The method and obtained results may facilitate understanding of minority carrier trap properties in wide bandgap semiconductor material and can be applied for device reliability assessment.

Carrier-induced formation of electrically active boron-interstitial clusters in irradiated boron-doped silicon

Excess minority carriers create boron-related recombination centers that degrade the efficiency of the non-particle-irradiated silicon solar cells. However, the carrier-induced reactions among the radiation-induced defects are poorly understood for devices exposed to particle radiation. This study investigates the structure, electronic properties, formation and annihilation mechanisms, and diffusion dynamics of the carrier-induced defects in particle-irradiated boron-doped silicon using density-functional modeling and junction spectroscopy. By revisiting the ground-state structures of the boron-di-interstitial clusters (BI2), we find that the calculated acceptor and donor levels of such defects agree well quantitatively with the carrier-induced deep-level transient spectroscopy (DLTS) hole emission signatures at 0.43 and 0.53 eV above the valence band edge (Ev), respectively. We also find that the formation of BI2 is thermally activated by an energy of 0.50 eV, which we explain theoretically by the reduction of the migration barrier of mono-interstitials to 0.53 eV in the presence of excess minority carriers. Moreover, we discover that the BI2 are potentially mobile with a migration barrier of 1.18 eV, contrary to the present understanding.

Polarized photoluminescence from Sn, Fe, and unintentionally doped β-Ga2O3

In this work, we demonstrate that β-Ga2O3 shows orientation-dependent polarized photoluminescence (PL) emission and give a comprehensive insight into gallium oxide's PL spectral properties. We characterized the polarization and spectral dependencies of both the incident and emitted light for (−201) unintentionally doped (UID) as well as (−201) and (010) Sn-doped and Fe-doped crystals. We observed for UID and Sn-doped samples that the electron to self-trapped hole and native defect-related emission bands are linearly polarized with polarized emission intensities ordered as E || c (and c*) > E || a (and a*) > E || b. Furthermore, the spectral shape of emission does not change between the UID and Sn-doped samples; instead, the Sn-doping quenches the total PL spectral intensity. For Fe-doped samples, polarized red emission caused by unintentional Cr3+ doping generates emission intensities ordered E || b > E || c (and c*) > E || a (and a*). It is also observed that in some circumstances, for some doped crystals, the PL spectra can show variations not only in intensity but also in spectral shape along different polarization directions. As an example, the PL emission band for emission along c is blueshifted relative to that along a in Sn-doped β-Ga2O3.

Influence of gate material and diamond surface termination on current conduction in metal/Al2O3/diamond capacitors

The current conduction in negatively biased metal/Al2O3/diamond capacitors with various gate materials and diamond surface terminations was comprehensively characterized by assuming a space-charge-controlled field emission (SCC-FE) process, yielding the following results. The current-feeding carriers were field-emitted from the electrode that had a barrier height lower than that of the opposing electrode. Specifically, in an Au-gate oxygen-terminated diamond capacitor, holes were likely to be emitted from the Al2O3/diamond interface states, whereas, in Al-gate oxygen-terminated, Au-gate hydrogen-terminated, and Al-gate hydrogen-terminated diamond capacitors, electrons were emitted from the gate. The barrier heights at the Al/Al2O3 and Au/Al2O3 interfaces were estimated as 1.6–1.7 and 2.8 eV, respectively. However, the analysis of the hole emission from the interface states is left for future studies. Although the substrate of the oxygen-terminated diamond capacitor remained weakly depleted even for highly negative gate voltages, the conduction current was observed as mentioned earlier. To analyze the mechanism for this conduction, the diffusion and drift currents in the depleted substrate were quantitatively estimated, ascribing the current conduction to the diffusion current. As these results could not be obtained by using the conventional graphical methods based on model-specific plots, such as the Fowler–Nordheim and Poole–Frenkel plots, the SCC-FE analysis proved to be a powerful tool for investigating the current conduction in metal-insulator-semiconductor capacitors.

Impact of the Accretion Disk Thickness on the Polarization of the Thermal Emission from Stellar Mass Black Holes

The Imaging X-ray Polarimetry Explorer, launched in 2021 December, enables precision measurements of the energy-dependent polarization of the X-ray emission from stellar mass and supermassive black holes. In this paper, we study the impact of the accretion disk geometry on the polarization of the thermal emission of mass-accreting stellar-mass black holes. We present a ray-tracing code that allows us to predict how the X-ray polarization energy spectra change as we dial up the thickness of the accretion disk from a geometrically thin accretion disk to a torus-shaped geometrically thick accretion disk. The results show that thicker disks can produce higher polarization degrees as the thick disk geometries lead to a larger fraction of X-rays reflecting off portions of the disk. We study the observational degeneracies between the disk shape on the one hand and the black hole spin and disk inclination on the other hand. We conclude with a discussion of the implications of our studies for black hole spin measurements.

Bandgap narrowing and hole self-trapping reduction in Ga2O3 by Bi2O3 alloying

Ga2O3 is an emerging material with attractive electrical properties for improving the performance of high-voltage power electronics, and it is widely accepted that engineering its band edge energies will expand its applications, especially for bipolar devices. In this work, monoclinic phase (BixGa1−x)2O3 ternary alloys are fabricated on c-plane sapphire via magnetron co-sputtering of Ga2O3 and Bi2O3. The bandgap of Ga2O3 is found to decrease from 4.97 to 4.78 eV by alloying with a Bi x-fraction of 0.04, consistent with the theoretical prediction that alloying with Bi2O3 causes the up-shift of the valence band. Concurrent temperature-resolved cathodoluminescence (CL) measurements of the Ga2O3 and (Bi0.04Ga0.96)2O3 are employed to investigate their intrinsic ultraviolet (UV) luminescence and defect-related visible bands with increasing temperature from 80 K. The CL results reveal a more rapid thermal quenching of the self-trapped hole (STH) emission with an activation energy of only 32 meV, suggesting that alloying with Bi2O3 lowers the self-trapping energy for holes. Temperature-dependent electrical measurements reveal the conductivity of the (Bi0.04Ga0.96)2O3 film is one order of magnitude lower than that of the undoped Ga2O3 counterpart; however, both possess an electrical activation energy of ∼ 26 meV, likely associated with an impurity-related shallow donor. The low electrical conductivity of (Bi0.04Ga0.96)2O3 can be attributed to the compensation of shallow donors by acceptors activated by the Bi2O3-induced upward shift of the valence band edge. The frequency-dependent conduction and ionic polarization mechanisms up to 107 Hz are found to be identical for Ga2O3 and (Bi0.04Ga0.96)2O3, indicating that the conduction in this ternary alloy does not involve the activation of Bi acceptors.

Adiabatic Radio Emission Spectrum of the Sun’s Coronal Holes

Coronal holes on the Sun have been observed at individual frequencies for quite a long time in the wavelength range from radio to X-rays. Observations in a wide range of radio frequencies are carried out with the RATAN-600 radio telescope. An analysis of long-term spectral observations of the RATAN-600 radio telescope showed that the emission spectrum of coronal holes is radically different from the spectrum of active formations above sunspots, but, differing markedly from the spectrum of the quiet Sun, it also has similarities with it. It has been established that the radio emission of coronal holes has an adiabatic spectrum and does not contain noticeable coherent radiation, that is, recombination radio lines and lines of the fine structure of hydrogen and other elements.

Numerical Simulation of Trapped Hole Lateral Migration and Induced Threshold Voltage Retention Loss in a SONOS Flash Memory

We establish a one-dimensional transient simulation to study trapped hole lateral migration in the silicon nitride of a silicon-oxide-nitride-oxide-silicon (SONOS) flash memory cell. In our model, the nitride traps have a continuous energy distribution. Trapped hole emissions to the valence band of the silicon nitride, free hole recapture into the nitride traps, and hole drift-diffusion in the valance band are included in the simulation. Two major trapped hole emission processes, thermally assisted tunneling (ThAT) and the Frenkel-Poole emission are considered. We simulate trapped hole lateral migration in a SONOS cell with program electrons stored at the source side and erase holes at the drain side. Our simulation shows that the ThAT is a dominant transport mechanism for trapped hole lateral migration in retention. We also simulate a threshold voltage (Vt) retention loss due to trapped hole lateral migration at different program levels. The trend of the simulated Vt retention loss is consistent with the measurement result.

Spruce bark beetles (Ips typographus) cause up to 700 times higher bark BVOC emission rates compared to healthy Norway spruce (Picea abies)

Abstract. Biogenic volatile organic compound (BVOC) emissions from trees subjected to biotic stress are higher compared to healthy trees, and they may also have a different compound composition. This in turn affects atmospheric chemistry and can lead to either positive or negative feedback to the climate. Climate change favors the abundance of the European spruce bark beetle (Ips typographus) which attacks the bark of Norway spruce (Picea abies) trees, causing induced BVOC emissions from the trees as a response to the insect stress. Here, results are reported from a study analyzing the difference in emission rates between healthy and bark-beetle-infested Norway spruce trees, changes in emission rates over time since the infestation started, and differences in emission rates from bark-beetle-drilled entry and exit holes. Bark chamber measurements on both healthy and infested trees were performed during the summer of 2019 at Hyltemossa and Norunda research stations in Sweden. The measurements showed that induced BVOC emissions following the bark beetle infestation were dominated by entry hole emissions in the early growing season and exit hole emissions in the later season. The results showed a significant difference in emission rates between healthy and infested trees during both seasons. The seasonal average standardized BVOC emission rate of healthy trees was 32 ± 52 µg m−2 h−1 (mean ± standard deviation), while the average standardized BVOC emission rates of infested trees were 6700 ± 6900 and 2000 ± 1300 µg m−2 h−1 during the early and late season respectively. BVOC emission rates were highest at the start of the infestation and decreased exponentially with time, showing induced emission rates for up to 1 year after which the emission rates were similar to those from healthy bark. Constitutive needle emission rates from healthy trees were found to be 11 times higher than bark emissions from healthy trees. However, when Norway spruce trees were infested, the bark emission rates were instead 6 to 20 times higher than the needle emissions, causing substantial increases in the total tree BVOC emission rate. This could lead to high impacts on atmospheric processes, specifically the formation of secondary organic aerosols, which have a higher yield from some monoterpene compounds, which increased from infested trees.

Fiber Optic Plate Coupled Pb-Free Perovskite X-ray Camera Featuring Low-Dose-Rate Imaging toward Dental Diagnosis.

Copper-based halide perovskites have been considered as promising scintillators. However, they still cannot meet the requirement of low-dose-rate X-ray imaging in medical diagnosis. Herein, we design a fiber optic plate (FOP) coupled perovskite X-ray camera to reduce the dose rate toward dental X-ray imaging. Tl doped Cs3Cu2I5 prepared via molten salt reaction has a high light yield of 72,000 photons/MeV, resulting from Tl10/Tl20-self-trapped hole emissions. After FOP coupling, the pulp cavity, root canal, dentin and root canal file can be clearly observed under a low dose rate as low as 3 μGyair s-1, which is absolutely lower than the required 5.5 μGyair s-1 for commercial intraoral dental sensors. The realization of such a low dose rate is attributed to the high coupling efficiency of 75% for the FOP and the high brightness of 262 lm m-2 for the scintillation screen. This designed portable X-ray camera shows its huge potential in intraoral dental X-ray imaging.

Photoluminescence from Be‐Doped GaN Grown by Metal‐Organic Chemical Vapor Deposition

A systematic photoluminescence study of Be‐doped GaN grown by metal‐organic chemical vapor deposition is presented. All Be‐doped samples show the ultraviolet luminescence (UVLBe) band with a maximum at 3.38 eV and the yellow luminescence (YLBe) band with a maximum at ≈2.15 eV in GaN:Be having various concentrations of Be. The UVLBe band is attributed to the shallow state of the BeGa acceptor with a delocalized hole. The YLBe band is caused by a Be‐related defect, possibly the polaronic state of the BeGa acceptor with the charge transition level at 0.3 eV above the valence band. This broad band exhibits unusual properties. In particular, it always shows two steps in its thermal quenching. The second step at T ≈ 200 K is attributed to the emission of holes from the 0.3 eV level to the conduction band. The origin of the first step remains unexplained.

Observations and Physical Insights Into Time-Dependent Hot Electron Current Confinement in AlGaN/GaN HEMTs on C-Doped GaN Buffer

In this work, we report a unique time-dependent evolution of drain current and hot electron distribution along the width of AlGaN/GaN HEMTs on C-doped GaN buffer during semi- ON state stressing. The drain current evolution with stress time exhibited two distinct phases, i.e., first, drain current reduction at lower stress times, which, second, is followed by an increase in the magnitude for longer stress times. Electroluminescence (EL) measurements revealed this to be accompanied by a transition in the hot electron distribution along the device width, from being uniform (during the current reduction phase) to being confined near the center of the device (during current increase phase). Detailed experiments involving measure-stress-measure (M-S-M) routine showed a gate-stack-dependent threshold voltage shift in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\text {SiN}}_{x}$ </tex-math></inline-formula> -gated MISHEMTs to be responsible for the reduction in the drain current. On the other hand, increase in the drain current and hot electron confinement were observed in Schottky as well as MIS-gated devices. Furthermore, in situ thermoreflectance-based temperature monitoring showed a nonuniform temperature distribution along the device width. Detailed computations, taking into account the nonuniform temperature distribution, established heating induced nonuniform hole emission along the device width and their subsequent lateral redistribution to be responsible for the experimentally observed current increase and hot electron confinement.

(Invited) Ferroelectric Field-Effect Transistors as High-Density, Ultra-fast, Embedded Non-Volatile Memories

Ferroelectric field-effect transistors (FEFETs) are receiving significant attention from the microelectronics community for next-generation memory technologies, especially as embedded non-volatile elements for data-centric applications. The main attractive features of FEFETs are that write energy and speed of FEFETs are within an order of magnitude of respective metrics for SRAMs (FEFET ~1 fJ and 1-10 ns vs. SRAM: <1 fJ and <1 ns), all the while requiring a significantly smaller cell size (FEFET 50-60F2 vs. SRAM 120-150F2) and close-to-zero standby leakage power – provided that FEFETs are integrated at the same advanced technology nodes as SRAMs [1]. In this talk, we will discuss the potential path for FEFET toward fulfilling this vision, by addressing the outstanding technological challenges: ultra-fast read-after write, reliability, voltage scaling and variation. To that end, our recent exposition on the trap and reliability physics of FEFETs will highlighted. We will highlight, based on newly developed experimental schemes, how the simultaneous capture and emission of electrons and holes in write cycles occur at the interface and the grain boundaries in the time domain, where in the band-diagram, these traps (acceptors and donors) are located and how exactly they result in the degradation of the read speed and reliability with continued write cycling. Based on these insights, we move on show how engineering the interfacial layer and the ferroelectric grain structure can enable ultra-fast read-after write and write voltage and dramatic improvements in reliability and variation, towards achieving a high-density, ultra-high speed memory technology.This research is supported by the National Science Foundation, the Defense Advanced Research Program Agency (DARPA), the Semiconductor Research Corporation (SRC) - Global Research Collaboration (GRC) program, the Applications and Systems-Driven Center for Energy-Efficient Integrated Nano Technologies (ASCENT), one of six centers in the Joint University Microelectronics Program (JUMP), a SRC program sponsored by the DARPA, and an Intel Rising Star award. [1] Mikolajick, T., Schroeder, U. & Slesazeck, S. The past, the present, and the future of ferroelectric memories. IEEE Trans. Electron Devices 67, 1434–1443 (2020).[2] Asif Islam Khan, Ali Keshavarzi, and Suman Datta. “The future of ferroelectric field-effect transistor technology." Nature Electronics 3.10 (2020): 588-597.

Traps in the spotlight: How traps affect the charge carrier dynamics in Cs2AgBiBr6 perovskite

Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs 2 AgBiBr 6 . However, efficiencies of Cs 2 AgBiBr 6 -based photovoltaics are still modest. To elucidate the loss mechanisms, in this report, we investigate charge dynamics in Cs 2 AgBiBr 6 films by double-pulse excitation time-resolved microwave conductivity (DPE-TRMC). By exciting the sample with two laser pulses with identical wavelengths, we found a clear photoconductance enhancement induced by the second pulse even 30 μs after the first laser pulse. Modeling the DPE-TRMC results, complemented by photoluminescence and transient absorption, we reveal the presence of deep emissive electron traps, while shallow hole trapping is responsible for the long-lived transient absorption signals. These long-lived carriers offer interesting possibilities for X-ray detectors or photocatalysis. The DPE-TRMC methodology offers unique insight into the times involved in charge trapping and depopulation in Cs 2 AgBiBr 6 . • Double-pulse excitation TRMC is developed to study trapping processes • Cs 2 AgBiBr 6 shows high photoconductance up to 30 μs after the first excitation • A high yield of free charges results from populated trap states by the first pulse • Emission of holes residing in shallow states extends over many microseconds Trap-assisted electron recombination in Cs 2 AgBiBr 6 thin films, combined with low hole mobility and shallow trapping, can be a major drawback of Cs 2 AgBiBr 6 in photovoltaic devices. Caselli et al. reveal that the long-lived charge carriers in Cs 2 AgBiBr 6 can offer a suitable, lead-free alternative for other applications, such as X-ray detectors or photocatalysis.

Degradation mechanisms of Mg-doped GaN/AlN superlattices HEMTs under electrical stress

GaN-based high electron mobility transistors (HEMTs) have exhibited great application prospects in power and radio frequency devices, thanks to the superior properties of GaN. Despite the significant commercialization progress, the reliability of GaN-based HEMTs remains a challenge. This work experimentally investigates the time-dependent degradation of Mg-doped GaN/AlN superlattice HEMTs under both OFF-state and SEMI-ON-state bias conditions and proposes that GaN/AlN superlattices as a barrier can solve the Vth instability issues of GaN HEMTs under OFF-state and SEMI-ON-state bias conditions. On the one hand, in the SEMI-ON-state, the hot electron effect leads to the degradation of Ig, gm,max, and Id,sat to varying degrees. However, the as-prepared GaN-based HEMTs exhibit excellent Vth stability (almost no change) under hot electron injection, on the account of the excellent two-dimensional electron gas confinement in the GaN/AlN superlattice structure. On the other hand, in the OFF-state, positive Vth shift (about 0.12 V) is induced by the hole emission in the GaN/AlN superlattice structure under reverse bias stress. In addition, the stress-induced destruction of MgO gate dielectric gives rise to the gate leakage, which increases by 2 orders of magnitude and triggers an irreversible degradation (about 10%) of the gm,max. These results are expected to provide a solution to the Vth instability of GaN HEMTs.

Mechanism of current-collapse free for lateral GaN Schottky barrier diodes utilizing polarization-induced hole injection

In this Letter, a mechanism of current-collapse free for high-performance lateral AlGaN/GaN Schottky barrier diodes (SBDs) with a thick single-crystal GaN cap layer is investigated. A high breakdown voltage of 1.74 kV and a low specific on-resistance (RON,sp) of 5.04 mΩ cm2 are achieved for the fabricated SBD with a spatial distance (LAC) of 15 μm. Benefiting from the optimized groove anode technique, including a low-damaged etching process and a post-anode-annealing process, a low leakage current of 87 nA/mm at −500 V as well as a low turn-on voltage of 0.8 V defined at an anode current density of 1 mA/mm are obtained. Holes induced by polarization effects at the GaN/AlGaN interface inject to the anode edge at the ON state, and the negatively charged centers induced by a groove etching process are neutralized, which lead to the suppressed tunneling current (ITU) and idealized ideality factor (η). The forward current density decreases due to the suppressed ITU at the barrier-limited region. When the devices are biased at the OFF state, holes around cathodes inject to the buffer layer, which suppress hole emission at the buffer layer, and current collapse is greatly suppressed even after a 300-s-long bias test at −600 V.

Temperature-Dependent Dynamic Performance of p-GaN Gate HEMT on Si

Temperature-dependent dc and dynamic characteristics of p-GaN gate HEMT were thoroughly investigated from 300 to 140 K. At low temperature, in addition to barely shifted threshold voltage, substantial improvement in drain current was observed. At 300 K both positive and negative gate bias stressing were applied to the device in order to form a complete mapping of threshold voltage instability of p-GaN gate HEMT. Three mechanisms, namely hole trap emission, carrier out-spilling, and hole accumulation have been employed to elucidate the trends of threshold voltage shift at room temperature. Temperature-dependent dynamic performances, including threshold voltage instability and drain current degradation, were investigated. Via drain current transient spectroscopy, activation energy for hole emission and trapping process were extracted as 132 and 70 meV, respectively. Detailed pulsed output characteristics at various quiescent biases were explored. At 300 K, gate quiescent bias played a dominant role in determining current collapse compared with drain quiescent bias. Moreover, current collapse caused by gate pulse stressing was much mitigated with decrease of temperature. The detailed temperature-reliant dynamic performance provides valuable information for justifying feasibility of p-GaN gate HEMT for low-temperature applications and further device optimizations.

High-Temperature Static and Dynamic Characteristics of 4.2-kV GaN Super-Heterojunction p-n Diodes

This article presents the static and dynamic characterization of 4.2-kV super-junction p-n diodes at high temperatures. Reduction of the forward current with increasing temperature is consistent with 2DEG mobility degradation caused by polar optical phonon scattering. Reverse leakage current was dominated by isolation leakage, with an activation energy of ~0.26 eV, close to the reported activation energy of surface leakage. Dynamic switching characterization in the temperature range from room temperature (RT) to 300 °C showed a nonmonotonic dependence of dynamic ON-resistance on temperature. At room temperature and 50 °C, devices showed zero current collapse (CC) up to OFF-state stress bias of 3 kV at 100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> timescale. Between 100 °C and 200 °C, significant CC was observed. From 250 °C to 300 °C, devices showed recovery from the severe CC. The degradation and recovery of dynamic ON-resistance can be explained by emission and recapture of holes during the OFF- and ON-states, respectively.