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In the preplanned interim analysis of the TOPAZ-1 study, durvalumab plus gemcitabine–cisplatin significantly improved overall survival versus placebo plus gemcitabine–cisplatin in participants with advanced biliary tract cancer. We aimed to report updated overall survival and safety data from TOPAZ-1 with additional follow-up and data maturity beyond the interim analysis.

We present femtosecond pump-probe measurements of neutral and charged exciton optical response in monolayer MoSe2to resonant photoexcitation of a given exciton state in the presence of 2D electron gas. We show that creation of charged exciton (X−) population in a given K+, K−valley requires the capture of available free carriers in the opposite valley and reduces the interaction of neutral exciton (X) with the electron Fermi sea. We also observe spectral broadening of the X transition line with the increasing X−population caused by efficient scattering and excitation induced dephasing. From the valley-resolved analysis of the observed effects we are able to extract the spin-valley relaxation times of free carriers as a function of carrier density. Moreover, we analyze the oscillator strength and energy shift of X in the regime of interaction with electron Fermi sea under resonant excitation. From this we can observe the process of X decay by radiative recombination paired with trion formation. We demonstrate an increase of neutral exciton relaxation rate with the introduction of Fermi sea of electrons. We ascribe the observed effect to the increased efficiency of the trion formation, as well as the radiative decay caused by the screening of disorder by the free carriers.

Competition between exchange interactions and magnetocrystalline anisotropy may bring new magnetic states that are of great current interest. An applied hydrostatic pressure can further be used to tune their balance. In this work, we investigate the magnetization process of a biaxial antiferromagnet in an external magnetic field applied along the easy axis. We find that the single metamagnetic transition of the Ising type observed in this material under ambient pressure transforms under hydrostatic pressure into two transitions, a first-order spin-flop transition followed by a second-order transition toward a polarized ferromagnetic state near saturation. This reversible tuning into a new magnetic phase is obtained in layered bulk CrSBr at low temperature by varying the interlayer distance using high hydrostatic pressure, which efficiently acts on the interlayer magnetic exchange and is probed by magneto-optical spectroscopy.

We report on magneto-optical studies of the quasi-two-dimensional van der Waals antiferromagnet FePS3. Our measurements reveal an excitation that closely resembles the antiferromagnetic resonance mode typical of easy-axis antiferromagnets; nevertheless, it displays an unusual, four-times larger Zeeman splitting in an applied magnetic field. We identify this excitation with an |Sz| = 4 multipolar magnon─a single-ion 4-magnon bound state─that corresponds to a full reversal of a single magnetic moment of the Fe2+ion. We argue that condensation of multipolar magnons in large-spin materials with a strong magnetic anisotropy can produce new exotic states.

Vitamin C (L-ascorbic acid) works as a strong reductant, radical scavenger, and protector of cell membranes against primary peroxidative damage in tissues and in the extracellular fluid. L-ascorbic acid is involved in the synthesis of collagen and many other biologically relevant substances, enzyme activity, xenobiotic detoxification, and prevention of forming carcinogenic nitrosamines. It also plays a role in the immune system. Numerous data indicate that cancer patients suffer from vitamin C deficiency. Studies show that people with a low vitamin C intake have an increased risk of head and neck cancers as well as lung, gastric, pancreatic, cervical, rectal, or breast cancer. On the other hand, there is no clinical evidence to support the thesis that antioxidant supplements (including vitamin C) prevent cancer. Observational trials investigating high doses of intravenous L-ascorbic acid in previously treated cancer patients have shown that it allows an increase in quality of life and may improve physical, mental, and emotional functions, as well as reducing adverse effects of standard anticancer treatment, including fatigue, nausea, vomiting, and appetite loss. So far, there were a few randomized controlled trials and they have not reported any statistically significant improvements in the overall or progression-free survival with vitamin C, as compared to the control arm. However, preclinical data indicating a role of L-ascorbic acid in modulation of immune response and its involvement in epigenome remodeling suggest its new potential clinical applications in cancer patients, especially in combination with immunotherapy. It seems reasonable to further investigate the value of vitamin C as a supportive treatment or in combination with anticancer targeted therapy.

Using ultrafast resonant pump-probe spectroscopy in an unconventional experimental setup we investigate the spectral shape and dynamics of absorption features related to the A exciton in an hexagonal boron nitride (hBN)/MoSe2/hBN van der Waals heterostructure. While in a pure two-level system a pump-probe experiment measures the occupation or the polarization dynamics, depending on the time ordering of the pulse pair, in the transition metal dichalcogenide (TMD) system both quantities get thoroughly mixed by strong exciton–exciton interaction. We find that for short positive delays the spectral lines experience pronounced changes in their shape and energy and they relax to the original situation on a picosecond time scale. For negative delays, distinctive spectral oscillations appear indicating the first-time observation of perturbed free induction decay for a TMD system. The comparison between co-circular and cross-circular excitation schemes further allows us to investigate the rapid inter-valley scattering. By considering a three-level system as a minimal model including the local field effect, excitation-induced dephasing (EID), and scattering between the excited states we explain all phenomena observed in the experiment with excellent consistency. Our handy model can be even further reduced to two levels in the case of a co-circular excitation, for which we derive analytic expressions to describe the detected signals. This allows us to trace back the spectral shapes and shifts to the impact of local field effect and EID thus fully reproducing the complex behavior of the observed effects.

We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of n-doped WS2monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Consequently, we identify emissions due to both the bright (singlet and triplet) and dark (spin- and momentum-forbidden) negative trions as well as the phonon replicas of the latter optically inactive complexes. The semidark trions and negative biexcitons are distinguished. On the basis of their experimentally extracted and theoretically calculated g-factors, we identify three distinct families of emissions due to exciton complexes in WS2: bright, intravalley, and intervalley dark. The g-factors of the spin-split subbands in both the conduction and valence bands are also determined.

Monolayer transition-metal dichalcogenides (TMDs) manifest exceptional optical properties related to narrow excitonic resonances. However, these properties have been so far explored only for structures produced by techniques inducing considerable large-scale inhomogeneity. In contrast, techniques which are essentially free from this disadvantage, such as molecular beam epitaxy (MBE), have to date yielded only structures characterized by considerable spectral broadening, which hinders most of the interesting optical effects. Here, we report for the first time on the MBE-grown TMD exhibiting narrow and resolved spectral lines of neutral and charged exciton. Moreover, our material exhibits unprecedented high homogeneity of optical properties, with variation of the exciton energy as small as ±0.16 meV over a distance of tens of micrometers. Our recipe for MBE growth is presented for MoSe2and includes the use of atomically flat hexagonal boron nitride substrate. This recipe opens a possibility of producing TMD heterostructures with optical quality, dimensions, and homogeneity required for optoelectronic applications.

The Landau level laser was proposed long ago as a unique source of monochromatic radiation that would be widely tunable in the THz and infrared spectral ranges using a magnetic field. However, despite many efforts, this appealing concept never progressed to the design of a reliable device. This is because of the efficient Auger scattering of Landau-quantized electrons, an intrinsic non-radiative recombination channel that eventually gains over cyclotron emission in all materials studied so far (conventional semiconductors with parabolic bands, but also in graphene with massless electrons). Auger processes are favoured in these systems because the Landau levels (or their subsets) are equally spaced in energy. Here, we show that this scheme does not apply to massless Kane electrons in gapless HgCdTe, where undesirable Auger scattering is strongly suppressed and sizeable cyclotron emission is observed. The gapless HgCdTe thus appears as a material of choice for future Landau level lasers.

We found that optical Aharonov–Bohm oscillations in a single GaAs/GaAlAs quantum ring can be controlled by excitation intensity. With a weak excitation intensity of 1.2 kW cm–2, the optical Aharonov–Bohm oscillation period of biexcitons was observed to be half that of excitons in accordance with the period expected for a two-exciton Wigner molecule. When the excitation intensity is increased by an order of magnitude (12 kW cm–2), a gradual deviation of the Wigner molecule condition occurs with decreased oscillation periods and diamagnetic coefficients for both excitons and biexcitons along with a spectral shift. These results suggest that the effective orbit radii and rim widths of electrons and holes in a single quantum ring can be modified by light intensity via photoexcited carriers, which are possibly trapped at interface defects resulting in a local electric field.

Supplemental Digital Content is available in the text.Vemurafenib, ipilimumab and dabrafenib were registered for the treatment of advanced skin melanoma pursuant to the results of randomized phase III clinical trials. Real-world data on survival time for patients treated with those drugs in daily clinical practice are so far limited. Patients with advanced skin melanoma treated under reimbursement programmes (drug programmes), for which they were qualified pursuant to uniform inclusion criteria in force in all oncology centres in Poland. Data were obtained from the electronic databases of the national payer (NFZ) responsible for the implementation and monitoring of reimbursement (drug) programmes. The analysis included all patients included for treatment with vemurafenib (since March of 2013), ipilimumab (since March of 2014) and dabrafenib (since July of 2015) until December 2016. The end date of the observation was set to 31 December 2016. The total survival analysis was performed using the Kaplan–Meier estimator. Until 31 December 2016, 759 patients were treated with vemurafenib, 370 with ipilimumab and 181 with dabrafenib. The overall survival (OS) median was 9.8 months for patients treated with vemurafenib (95% confidence interval: 8.8–10.6) and 6.9 months for patients treated with ipilimumab (95% confidence interval: 5.7–9.2). For patients treated with dabrafenib, the OS median was not reached because of an overly short observation period. The probability of surviving 12 months in the group of patients treated with vemurafenib was 40.5%, ipilimumab was 35.1% and dabrafenib was 60.7%. The probability of surviving 24 and 36 months in the group of patients treated with vemurafenib or ipilimumab amounted to, respectively, 20.1, 15.4 and 21, 18.8%. OS of patients with advanced melanoma treated in daily clinical practice may be comparable to the ones achieved in registration trials. The use of appropriate treatment inclusion criteria may affect the obtained OS.

Recent results on the optical properties of monolayer and few layers of semiconducting transition metal dichalcogenides are reviewed. Experimental observations are presented and discussed in the frame of existing models, highlighting the limits of our understanding in this emerging field of research. We first introduce the representative band structure of these systems and their interband optical transitions. The effect of an external magnetic field is then considered to discuss Zeeman spectroscopy and optical pumping experiments, both revealing phenomena related to the valley degree of freedom. Finally, we discuss the observation of single photon emitters in different types of layered materials, including wide band gap hexagonal boron nitride. While going through these topics, we try to focus on open questions and on experimental observations, which do not yet have a clear explanation.

Temperature-dependent (5 K–300 K) Raman scattering study of A1g/A′1phonon modes in mono-layer (1L), bilayer (2L), trilayer (3L), and tetralayer (4L) MoTe2is reported. The temperature evolution of the modes’ intensity critically depends on the flake thickness. In particular with λ=632.8-nm light excitation, a strongly non-monotonic dependence of the A1gmode intensity is observed in 2L MoTe2. The intensity decreases with decreasing temperature down to 220 K, and the A1gmode almost completely vanishes from the Stokes scattering spectrum in the temperature range between 160 K and 220 K. The peak recovers at lower temperatures, and at T=5 K, it becomes three times more intense that at room temperature. Similar non-monotonic intensity evolution is observed for the out-of-plane mode in 3L MoTe2in which tellurium atoms in all three layers vibrate in-phase. The intensity of the other out-of-plane Raman-active mode (with vibrations of tellurium atoms in the central layer shifted by 180° with respect to the vibrations in outer layers) only weakly depends on temperature. The observed quenching of the Raman scattering in 2L and 3L MoTe2is attributed to a destructive interference between the resonant and non-resonant contributions to the Raman scattering amplitude. The observed “antiresonance” is related to the electronic excitation at the M point of the Brillouin zone in few-layer MoTe2.

The R-lines of the Mn4+fluorescence, associated with 2transitions in gadolinium gallium garnet exhibits large broadening as compared with other ions with d3shell. The laser excitation and fluorescence spectra without magnetic field show that this is partially inhomogeneous broadening related to presence of charge-compensating Ca2+ions. Remaining part of the broadening is due to antiferromagnetic exchange interaction between Mn4+and surrounding them six Gd3+ions. The high magnetic field up to 20 T has been used to resolve the spectra broadened by spin-spin interaction. The estimated value of the spin-spin exchange constant is equal to j ≈ 1.9 cm-1.

Local laser excitation and temperature readout from the intensity ratio of Stokes to anti-Stokes Raman scattering signals are employed to study the thermal properties of a large graphene membrane. The concluded value of the heat conductivity coefficient κ ≈ 600 W/(m·K) is smaller than previously reported but still validates the conclusion that graphene is a very good thermal conductor.

The article discusses teacher compensation. It notes that the No Child Left Behind Act focuses on teacher qualifications as inputs, which have been shown not to correlate with academic achievement. The Race to the Top fund tries specifically to align teacher pay with evidence of effectiveness. It notes that research is ongoing and no conclusive results exist to date, but that pay issues need to be part of a larger system of teacher quality reforms.

We report the photoluminescence experiments on high quality GaN samples in high magnetic fields. A detailed analysis of the recombination due to excitons bound to neutral donors and acceptors is presented. Special attention is focussed on transitions for which the impurity is left in the excited state (so called two electron satellites). These results show a rich energetic structure of excited states of the impurity involved in such a recombination process. The magnetic field dependence of the energy structure of the shallow neutral donor and acceptor in GaN is then discussed. The validity of the effective mass approximation for shallow impurities in wide gap semiconductors is examined. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

There are three exciton branches in wurzite-GaN: A, B and C. Here, time-resolved photoluminescence and magneto-optic spectroscopy of the B-exciton are presented, both free (FXB) and bound to donor (D⁰XB) in homoepitaxial GaN. The free B-exciton has an energy of about 3.483 eV and a very short lifetime of about 20 ps. The B-exciton bound to donor (D⁰XB) has an energy of 3.475 eV and a lifetime longer than the free excitons but shorter than the lifetime of the A-exciton bound to donor. It is shown that a simple model based on an invariant expression describes properly the behavior of D⁰XA and D⁰XB in a magnetic field. Results of resonance excitation experiments suggest that in many cases the process of binding a free exciton to a donor conserves the exciton type and that the relaxation of B- to A-exciton takes place later. Moreover, thermal excitation of D⁰XA to D⁰XB has been observed.

Magneto-luminescence experiments performed on a thick, freestanding GaN layer in magnetic fields up to 28 T are presented. The photoluminescence spectrum of this material shows narrow emission lines due to neutral donor-bound excitons (D⁰X). In addition to the principal recombination channel of D⁰X in which the donor is left in its ground state, two-electron satellites (TES) involving different excited donor states, as well as LO phonon replica of the principal and satellite transitions are observed. For the magnetic field range in which internal donor excitations are tuned into resonance with the LO phonon excitations, the intensity of TES is strongly enhanced. A clear resonant interaction between TES corresponding to the highly excited donor states (n > 4) and LO phonon replica of D⁰X is observed. The observed effect is discussed in terms of electron–phonon interaction.

There are three exciton branches in wurzite-GaN: A, B and C. Here, time-resolved photoluminescence and magneto-optic spectroscopy of the B-exciton are presented, both free (FXB) and bound to donor (D0XB) in homoepitaxial GaN. The free B-exciton has an energy of about 3.483 eV and a very short lifetime of about 20 ps. The B-exciton bound to donor (D0XB) has an energy of 3.475 eV and a lifetime longer than the free excitons but shorter than the lifetime of the A-exciton bound to donor. It is shown that a simple model based on an invariant expression describes properly the behavior of D0XA and D0XB in a magnetic field. Results of resonance excitation experiments suggest that in many cases the process of binding a free exciton to a donor conserves the exciton type and that the relaxation of B- to A-exciton takes place later. Moreover, thermal excitation of D0XA to D0XB has been observed.

Magneto-luminescence experiments performed on a thick, freestanding GaN layer in magnetic fields up to 28 T are presented. The photoluminescence spectrum of this material shows narrow emission lines due to neutral donor-bound excitons (D0X). In addition to the principal recombination channel of D0X in which the donor is left in its ground state, two-electron satellites (TES) involving different excited donor states, as well as LO phonon replica of the principal and satellite transitions are observed. For the magnetic field range in which internal donor excitations are tuned into resonance with the LO phonon excitations, the intensity of TES is strongly enhanced. A clear resonant interaction between TES corresponding to the highly excited donor states (n > 4) and LO phonon replica of D0X is observed. The observed effect is discussed in terms of electron–phonon interaction.

We report on the results of high-magnetic-field (up to 28T) inelastic light scattering measurements of coupled plasmon–phonon modes in metallic GaAs samples with electron concentrations ranging from 1017to 2×1018cm−3. The zero-field Raman spectra of the investigated samples show peaks related to the transverse optical phonon (TO) as well as the coupled plasmon–phonon ω−(below TO frequency) and ω+(above LO frequency) modes. In the backscattering Voigt geometry (k⊥B) in which the modes propagating across the field direction are probed, the magnetic field does not influence the TO resonance but leads to a splitting of both ω+and ω−branches. The experimental data are approximated using the dielectric function formalism. For a highly doped sample, the interaction between coupled plasmon–phonon modes with the Bernstein mode is observed.

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We present interband magneto-absorption spectra up to 20 T taken at 2 K for 100 Å CdTe and CdMnTe single and multiple quantum wells containing a two-dimensional electron gas with concentrations ne up to 4 × 1011 cm—2. Without magnetic field B the absorption spectrum is characterized by two strong peaks, whose energy difference increases linearly with the electron concentration ne. This is interpreted in the framework of the many-body theory proposed by Hawrylak. In a magnetic field B, the spectra of high ne (4 × 1011 cm—2) quantum wells show circularly polarized absorption lines. We find that: (i) asBis increased there is a dominant, strongly enhanced absorption transition whose position is related to the zigzags of the Fermi level on the conduction band Landau levels; (ii) at integer values of the filling factorν, in absorption spectra, there is a sudden redshift of this line equal to the cyclotron energy of the electron ħωeh ; (iii) between the discontinuities, in emission spectra, the values of the transition slope are nħωeh (i.e. not the expected values (n + 1/2) ħωeh) where n is the Landau level index and ħωeh represents the sum of the cyclotron energy of the electron and the hole.

Magnetic layered materials have emerged recently as promising systems to introduce magnetism in structures based on two-dimensional (2D) materials and to investigate exotic magnetic ground states in the 2D limit. In this work, we apply high hydrostatic pressures up to P≈ 8.7 GPa to the bulk layered antiferromagnet FePS3to tune the collective lattice excitations (phonons) in resonance with magnetic excitations (magnons). Close to P= 4 GPa, the magnon-phonon resonance is achieved, and the strong coupling between these collective modes leads to the formation of new quasiparticles, the magnon-polarons, evidenced in our low-temperature Raman scattering experiments by a particular avoided crossing behavior between the phonon and the doubly degenerate antiferromagnetic magnon. At the pressure-induced magnon-phonon resonance, three distinct coupled modes emerge. As it is mainly defined by intralayer properties, we show that the energy of the magnon is nearly pressure-independent. We additionally apply high magnetic fields up to B= 30 T to fully identify and characterize the magnon excitations and to explore the different magnon-polaron regimes for which the phonon has an energy lower than, equal to, or higher than the magnon energy. The description of our experimental data requires introducing a phonon-phonon coupling not taken into account in actual calculations.

Magnetic field studies of circularly polarised emission due to free and bound excitons in high quality homoepitaxial GaN layers are presented. The conventional analysis of the band structure of the wurtzite-type symmetry allowed us to determine both the signs and the values of the effective Landé g-factors for electrons and holes participating in the recombination of free excitons originating from Γ9 and Γ7 valence band components as well as for electrons and holes weakly bound to donor and acceptor centres. The magnetic field splitting scheme of the conduction and the valence band is examined. The fine structure of the excitonic emission is also discussed.

We have studied the temperature dependence of the spin-flip processes of electrons in p-type modulation-doped GaAs quantum wells. We have found that at low temperature (T ≤ 30 K) the exchange interaction between electrons and holes is the main mechanism responsible for the spin-flip of the electrons, whereas at higher temperatures the so-called Dyakonov-Perel mechanism dominates. Furthermore, we have found that the recombination time increases considerably with increasing lattice temperature from a value of τr  200 ps at 5 K to τr  400 ps at 60 K.

The phenomenon of “meniscus lines” on the surfaces of liquid phase epitaxial layers of GaAs is described, and it is shown that these are associated with a “stick-slip” motion of the edge of the liquid as it is removed from the surface. Mechanisms which may account for the creation of this phenomenon are postulated.

Abstract: The incorporation of carbon into GaAs grown by metal-organic vapor phase epitaxy has been studied through the addition of CH2I2, CH3I, HI and I2 to the growth ambient. The epitaxial GaAs was grown using Ga(CH3)3 and AsH3 in a low pressure reactor. The addition of CH2I2 to the growth ambient resulted in the controlled incorporation of carbon. The addition of CH3I, HI and I2 did not result in any additional carbon incorporation. The decomposition of CH2I2 may result in the formation of methylene, CH2, on the growth surface. A reaction mechanism that explains the incorporation of carbon by CH2I2 and the implication of these results during conventional growth are discussed.

The laser excitation and luminescence spectra of the R-lines of the Mn4+ in gadolinium gallium garnet show that the large broadening which they exhibit is partially related to presence of charge-compensating Ca2+ ions, even for the case of manganese center without close compensation. Remaining part of the broadening is due to antiferromagnetic exchange interaction between Mn4+ and surrounding them six Gd3+ ions. The spectra remain broadened in magnetic fields below 6 T and the higher magnetic fields up to 20 T removes the broadening related to the spin-spin interaction. Luminescence and excitation spectra at 2.2 K show that the transitions occur between levels which magnetic numbers differ by 0 or ± 1. The estimated value of the spin-spin exchange constant for the ground state of Mn4+ is approximately equal to J ≈ 1.9 cm-1.

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Recent magnetoluminescence results obtained for homoepitaxial GaN layers are presented. The neutral impurity-bound excitons and donor–acceptor pair emission lines have been studied in magnetic fields up to 27 T. Low-temperature luminescence spectra have been measured with the magnetic field parallel and perpendicular to the hexagonal c-axis of the GaN layers. Experimental results allowed us to evaluate diamagnetic shifts, effective g-factors of electrons and holes involved in neutral donor and neutral acceptor complexes as well as the electron–hole exchange constant for close donor–acceptor pairs. Both the fine structure of the neutral acceptor-bound exciton emission and the specific properties of donor–acceptor pair spectra observed in magnetoluminescence experiments are tentatively attributed to the internal structure of the acceptor state.

Abstract: Oxygen has always been considered to be a major contaminant in the organo-metallic vapor phase epitaxy (OMVPE) of Al x Ga1−x As. Oxygen incorporation has been invoked as a contributor to low luminescence efficiency, dopant compensation and degradation of surface morphology among other deleterious effects. This study presents quantitative measurements of oxygen concentration in nominally high purity Al x Ga1−x As. The oxygen concentration was measured as a function of alloy composition, growth temperature, andV/III ratio. Quantitative secondary ion mass spectroscopy (SIMS) measurements were used to determine the oxygen content as well as the carbon concentration in the film. The oxygen concentration increases with decreased growth temperature and V/III ratio while increasing superlinearly with Al content in the epitaxial layer.

The purpose of our study was to determine the effectiveness of 2-CdA in 2-hour intravenous infusions in the treatment of B-CLL. One hundred and ten patients with B-CLL received 1 to 10 courses of 2-CdA (median 2.5) at a dosage of 0.12 mg/kg daily for 5 consecutive days. Eighteen of them were untreated and 92 relapsed or became refractory to previous therapeutic modalities. Complete remission (CR) was achieved in 8 (7.3%) and partial remission (PR) in 35 patients (31.8%) giving an overall response rate of 39.1%. In 3 patients, cross-resistance to fludarabine was noticed. Toxic effects of 2-CdA were more frequently observed in previously treated patients. Hemorrhagic complications due to drug-induced thrombocytopenia were noticed in 25 (22.7%) and severe infections including sepsis in 14 (12.7%) patients.

The luminescence of n-type modulation doped GaAs/GaAlAs single quantum well structures has been used to probe the relaxation processes in the presence of quasi two dimensional electron gas under high magnetic fields. It was found that the magnetic field induced modulation of the Landau levels separation and occupation strongly alters the relaxation processes. In the Quantum Hall Effect regime the nonradiative relaxation processes through the localized states between Landau levels are strongly enhanced due to the reduction of the screening.

Controlled oxygen incorporation in GaAs using Al-0 bonding based precursors, dimethyl aluminum methoxide (DMALO) and diethyl aluminum ethoxide (DEALO), is presented in this investigation. A comparison study of oxygen incorporation kinetics between nominally undoped AlxGa1−xAs using trimethyl aluminum and DMALO-doped GaAs suggests that DMALO is one of the most important oxygen-bearing agents responsible for unintentional oxygen incorporation in AlxGa1−xAs. Controlled oxygen doping using DEALO is reported for the first time. Oxygen incorporation behavior, especially on the effect of the V/III ratio, was found to be quite different from the case of DMALO, mainly due to the differences between methyl- and ethyl-based growth chemistries. Physical, electrical, and optical properties of these oxygen-doped GaAs are also reported.