We have determined effective mass parameters for ultrapure diamond by time-resolved cyclotron resonance of optically excited carriers. The transverse and longitudinal electron masses are found to be ${m}_{t}/{m}_{0}=0.280(2)$ ${m}_{l}/{m}_{0}=1.56(2)$, where ${m}_{0}$ is the free-electron mass. Luttinger extracted as ${\ensuremath{\gamma}}_{1}=2.67(2),\phantom{\rule{0.28em}{0ex}}{\ensuremath{\gamma}}_{2}=\ensuremath{-}0.40(2)$, ${\ensuremath{\gamma}}_{3}=0.68(2)$, which give light-...

We have performed time-resolved cyclotron resonance measurements in ultrapure diamond crystals for the temperature range of T=7.3–40 K and obtained temperature-dependent momentum relaxation times based on widths optically generated electrons holes. The time follows a T−3/2 law down to 12 K, which is expected acoustic-phonon scattering without impurity effect because high purity our samples. deviation from at lower temperatures explained by breakdown high-temperature approximation phonon...

We show that in a magnetic field B the otherwise forbidden lowest exciton Cu2O (paraexciton of Gamma(2)(+) symmetry) gives rise to narrow absorption line 80 neV at temperature 1.2 K. The B2 dependence field-induced oscillator strength and low energy shift DeltaE with increasing are measured. From two-phonon excitation spectroscopy measurements we derive by merely kinematical analysis very reliable value for paraexciton mass. A blueshift broadening observed intensity. These observations...

We investigated the photoluminescence spectra of ${\mathrm{Cu}}_{2}\mathrm{O}$ under photoexcitation at 3.05 eV across violet band gap. The following three features were found: from blue and excitons; yellow excitons $s,d$, $f$ states in addition to $p$ with a quantum number up ten; emissions associated inelastic collision $1s$ excitons. first process is relevant for separation radiative nonradiative decay rates. second likely indicates enhancement high Rydberg last verifies up-conversion...

We have demonstrated cyclotron resonance with a temporal resolution of 15 ns by using an electron-spin-resonance cavity. In undoped direct-gap semiconductor, cuprous oxide, we observe clear low-field shifts the peaks shortly after generation photoexcited carriers. Based on plasma shift resonance, evaluate carrier density and quantitatively discuss interaction between free carriers excitons. With increasing time delay, hole asymptotically reaches constant value corresponding to effective mass...

Abstract Abstractauthoren Exciton diffusivity and carrier mobility are key features in determining transport properties of a material. The optimum values required for high‐performance devices expected to be realized undoped intrinsic materials. Diamond, one the emergent high‐mobility materials, has wide band gap suited use power electronics optoelectronics. For many years, however, measurement diamond been limited by freezing at deep impurity levels. Recently, attempts utilizing photoexcited...

We present experiments on the luminescence of excitons confined in a potential trap at milli-Kelvin bath temperatures under cw-excitation. They reveal several distinct features like kink dependence total integrated intensity excitation laser power and bimodal distribution spatially resolved luminescence. Furthermore, we discuss state theoretical description Bose-Einstein condensation with respect to signatures condensate The comparison experimental data results as well shows necessity taking...

We present experiments on the luminescence of excitons confined in a potential trap at sub-Kelvin temperatures after nanosecond pulsed laser excitation. Analysis experimental results with rate model shows that so-called Auger decay yellow excitons, which previous studies led to rapid high densities and thus prevented reaching critical density for Bose–Einstein condensation (BEC), is greatly reduced paraexcitons. demonstrate exciton numbers well above 1010 can be collected trap, albeit 10 K...

We have found a series of resonances associated with the bound state (polyexcitons, PE(N)s) N excitons up to N=6 in emission spectra diamond under two-photon excitation at around 10 K. Time-resolved show stepwise formation PE(N)s smaller larger N, as well successive decay from N. At higher levels, transformation into condensed phase electron-hole droplets occurs. The binding energies PE(N)s, normalized exciton Rydberg energy, agree those silicon, suggesting universality phenomena.

We have investigated fine structure splitting of indirect excitons in ultrapure diamond by high-resolution spectroscopy. The role the mass-anisotropy has been revealed comparison with group-theoretical calculations reduced matrix elements for phonon scattering electrons and holes followed radiative recombination. observed energy levels coupling strengths states are successfully reproduced inclusion addition to exchange spin-orbit interactions.

We have demonstrated size-dependent radiative coupling in a ${\mathrm{Cu}}_{2}\mathrm{O}$ mesoscopic film, where the spatial matching between center-of-mass exciton motion and light waves plays an essential role. The observed quadratic increase oscillation of photoluminescence intensity with varying film thicknesses (16--1000 nm) indicate nonlocal response that is unique to systems. Optimally, ${10}^{4}$-fold enhanced rate was found compared bulk ${\mathrm{Cu}}_{2}\mathrm{O}$. A new degree...

The basic theoretical foundation for the modeling of phonon-assisted absorption spectra in direct band-gap semiconductors, introduced by Elliott 60 years ago [R. J. Elliott, Phys. Rev. 108, 1384 (1957)] using second order perturbation theory, results a square root shaped dependency close to edge. A careful analysis experiments [N. Naka et al., Jpn. Appl. 44, 5096 (2005)] reveals that yellow S excitons ${\mathrm{Cu}}_{2}\mathrm{O}$ lineshape does not follow dependence. reexamination theory...

A fundamental understanding of the photoexcited carrier system in diamond is crucial to facilitate its application photonic and electronic devices. Here, we studied detailed balance between free carriers excitons pristine by using a deep-ultraviolet (DUV) pump combination with terahertz (THz) probe spectroscopy. We investigated transformation via an internal transition excitons, which was newly found occur at frequency approximately 15 THz. determined equilibrium constant Saha equation from...

Ultrafine splittings are found in the optical absorption spectra of boron-doped diamond measured with high resolution. An analytical model an exciton complex is developed, which permits assigning all lines and sizing interactions among constituent charges crystal field. We conclude that entry split-off holes acceptor-bound fine structure yields two triplets separated by a spin-orbit splitting 14.3 meV. Our findings thereby resolve long-standing controversy [R. Sauer et al., Revised excitons...

We have measured transients of excitonic luminescence under pulsed excitation single-crystal diamond, synthesized by a high-temperature high-pressure method. The longest decay time 80 ns is at lattice temperature around 100 K in nondoped samples. kinetics strongly depends on the power density and impurity concentration. Based concentrations determined from infrared ultraviolet absorption coefficients, we simulate carrier solving rate equations for free bound exciton densities. It found that...

The phonon-assisted optical transitions of excitons in intrinsic diamond have been investigated theoretically and experimentally. Excellent agreement is indicated between absorption spectra measured calculated based on the phonon coupling strengths from first-principles calculations using just a single adjustable parameter. Temperature shift broadening are incorporated via pseudo-Voigt function analysis developed for derivative experimental spectra. coefficients discrete continuum states...

Abstract We have observed edge emission due to free excitons and electron–hole droplets in diamond by two‐photon excitation using subpicosecond laser pulses at 257 nm. find that excitonic temperatures under are much lower than the case of one‐photon excitation. A minimum temperature 3.4 K is extracted spectral analysis. In order understand difference excitations, we discuss a heating mechanism which depends on density distribution pairs crystal along beam. (© 2008 WILEY‐VCH Verlag GmbH &...

Spectrally and spatially resolved measurements of yellow 1$S$ orthoexcitons paraexcitons Cu${}_{2}$O in strain-induced traps are presented. Trap depths up to 31 meV for 23 achieved. In addition, a magnetic field 10 T is applied. With theoretical model taking into account the strain- magnetic-field-induced mixing green excitons, experimental data trap-depth-dependent magnetic-field-dependent shifts can be explained. Furthermore, polarization dependence emission trapped investigated. Spatially...

We investigate the lifetime and luminescence quantum efficiency of excitons in extremely high-purity diamond grown by chemical vapor deposition method. A clear correlation is found between diffusion coefficient, lifetime, efficiency. The effect small strain (magnitude $\ensuremath{\approx}{10}^{\ensuremath{-}5}$) assessed using birefringence also clarified thanks to effective absence impurity traps. surface recombination model, extended for nonradiative at dislocations due diffusion,...

Two-photon spectroscopy is applied to stress-induced exciton traps for $1s$ yellow excitons in ${\mathrm{Cu}}_{2}\mathrm{O}$ crystals at 1.6 K. The resonance emission lines associated with orthoexcitons and paraexcitons are used measure the shape depth of respective species excitons. luminescence from shows well-resolved structure suggesting their drift motion toward bottom trap. transit time evaluated be $0.2 \ensuremath{\mu}\mathrm{s}$ peak energy structure. This value comparable decay...