Ultrafast relaxation and absorption saturation at near exciton resonance in a thin ZnO epilayer

Ou, Po-Chi; Liu, Wei-Rein; Ton, Ho-Jei; Lin, Ja‐Hon; Hsieh, Wen–Feng

doi:10.1063/1.3525993

Cited by 17 publications

(11 citation statements)

References 27 publications

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“…Similar values (1.2 ps, 0.81 ps and 0.69 ps) have been reported earlier [14] for the unspecified photogenerated carrier density. The most recent time-resolved pump-probe optical measurements with the given photogenerated carrier density report slightly shorter relaxation times at higher densities: 0.77 ps [15] and 0.85 ps-0.7 ps [13] (Fig.3, open square and triangle). Other optical time-resolved measurements yielded the following relaxation times: 1ps [7], [8], 0.98 ps [9], 0.86 ps [10], 1 ps [11], 0.8 ps [12], 1.75ps and 0.2 ps [3], <3.5ps [24], <4.5ps [25] and <30fs [6].…”

Section: Discussionmentioning

confidence: 87%

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Electron energy relaxation in wurtzite ZnO and GaN

Šermukšnis¹,

Ramonas²,

Liberis³

et al. 2013

2013 22nd International Conference on Noise and Fluctuations (ICNF)

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Experimental data and Monte-Carlo modeling of hot-electron fluctuations are used for investigation of hot-electron energy relaxation in donor-doped bulk wurtzite ZnO and GaN subjected to a pulsed dc. The extracted electron energy relaxation time depends on the electron density. The experimental value of 0.84 ps is obtained at 5.5x10 17 cm −3 in a reasonably good agreement with the results reported from time-resolved optical measurements. The relaxation becomes faster at a lower electron density where the optical data are not available. The density dependence is discussed in the frame of hot-phonon effect. ICNF2013978-1-4799-0671-0/13/$31.00 c ⃝2013 IEEE

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Section: Discussionmentioning

confidence: 87%

“…Solid lines in Fig. 2 illustrate the semi-empiric Open symbols illustrate the most recent optical measurements: circles [16], square [15] and triangles [13].…”

Section: Hot-electron Fluctuation Measurementsmentioning

confidence: 99%

Electron energy relaxation in wurtzite ZnO and GaN

Šermukšnis¹,

Ramonas²,

Liberis³

et al. 2013

2013 22nd International Conference on Noise and Fluctuations (ICNF)

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“…We suppose that the excess hot-electron temperature T e -T b approximately equals the excess noise temperature T n -T b (Figure 7). [22], bullets -worldwide results measured by photoexcitation techniques [8][9][10][11][12][13][14][15][16][17][18][19][20]. Dotted curve is semi-empirical dependence [36].…”

Section: Experimental Datamentioning

confidence: 99%

Window for Optimal Frequency Operation and Reliability of 3DEG and 2DEG Channels for Oxide Microwave MESFETs and HFETs

Matulionis¹

2016

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Air Force Materiel Command REPORT DOCUMENTATION PAGE The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

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“…9 Nevertheless, to manufacture ultrafast semiconductor devices, it is crucial to investigate ultrafast carrier dynamics through time-resolved measurement (TRM). The transient carrier behaviors of c-ZnO through the excitation of ultrashort fs lasers have been widely explored in various structures, such as quantum dots, 10 nanowires, 11 multiple quantum wells, 12 thin films, 13 single crystals, 14 etc. For instance, Ou et al reported the thickness related ultrafast carrier dynamics of c-ZnO epifilm through the degenerate pump-probe technique using far-above-bandgap excitation.…”

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confidence: 99%

“…In addition, the TRM has also been adopted to discuss the electron and hole dynamics from a 97 nm non-polar a-ZnO epifilm through two orthogonal pump polarization (E pu ) configurations, i.e., perpendicular (E pu ⊥c) and parallel (E pu c) electric fields relative to the c-axis. 16 Owing to the large binding energy of ZnO compared with other semiconductor materials, RT transient excitonic dynamics 13 are crucial for developing stabilized luminant devices, but the exciton dynamics have seldom been studied. In a previous report, 16 the main work focused on the ultrafast carrier dynamics of a 97 nm non-polar a-ZnO epifilm above and near the bandedge.…”

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confidence: 99%

Room temperature excitonic dynamics of non-polar a-plane ZnO epifilms

Lin

Liu

et al. 2016

AIP Advances

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Pump polarization dependent carrier dynamics, particularly excitonic dynamics, of non-polar a-plane zinc oxide (ZnO) epifilms with two different thicknesses were investigated using time resolved measurements. Unlike the electron and hole dynamics through the above-bandgap excitation, transient differential reflectance (TDR) traces revealed similar trends under two orthogonal pump polarization conditions relative to the c-axis (Epu⊥c and Epu∥c) of a-ZnO around near-exciton-resonance excitation. By means of a band diagram, the bandgap renormalization (BGR) effect can be reasonably explained by the screening of the Coulomb potential energy due to the accumulation of relaxed free carriers that were initially excited through the absorption of two cascaded pump photons via the excitonic level, a process known as two photon absorption (TPA). Thus, the modulation depths of the TPA around zero time delay, due to simultaneous absorption of one pump and one probe photon via the excitonic level, increased linearly with the pump fluence, proportional to the modulation depth resulting from the BGR effects.

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Ultrafast relaxation and absorption saturation at near exciton resonance in a thin ZnO epilayer

Cited by 17 publications

References 27 publications

Electron energy relaxation in wurtzite ZnO and GaN

Electron energy relaxation in wurtzite ZnO and GaN

Window for Optimal Frequency Operation and Reliability of 3DEG and 2DEG Channels for Oxide Microwave MESFETs and HFETs

Room temperature excitonic dynamics of non-polar a-plane ZnO epifilms

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