Effect of pressure on the low-temperature exciton absorption in GaAs

Goi, A. R.; Cantarero, A.; Syassen, K.; Cardona, M.

doi:10.1103/physrevb.41.10111

Cited by 134 publications

(81 citation statements)

References 34 publications

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“…The conduction band minimum at L-is a M 0 -point. Therefore, from the analysis of the absorption edge through the Elliot-Toyozawa equation with Gaussian convolution [13], one can calculate some 300 meV for the exciton ionisation energy. An estimate of about 5 for the relative electronic dielectric constant may be made by comparing the photon energy at which the main absorption peak occurs in CuScO 2 and CuAlO 2 to that of CuInO 2 , an electronically similar material, which has a dielectric constant of 4.2 [14].…”

Section: Discussionmentioning

confidence: 99%

Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Gilliland

Pellicer‐Porres

Segura

et al. 2006

Physica Status Solidi (b)

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The electronic structure of CuAlO 2 and CuScO 2 delafossites is investigated by means of optical absorption measurements under pressure and ab initio band structure calculations. Measurements are carried out on CuAlO 2 monocrystals and pulsed laser deposited CuAlO 2 and CuScO 2 thin films up to 20 GPa. CuAlO 2 is an indirect semiconductor that is stable in the pressure range explored here. The pressure coefficients of the indirect and direct gaps are found to be 15 meV/GPa and 2 meV/GPa respectively. CuScO 2 is a direct semiconductor and the pressure coefficient of the excitonic peak energy is -5.5 meV/GPa. Two reversible phase transitions are observed in CuScO 2 . At 13 GPa the delafossite structure becomes unstable and an unidentified intermediate high pressure phase is observed, which coexists with the delafossite phase up to 18 GPa. The intermediate phase is also a wide gap semiconductor, with an step-like absorption edge at the energy of 3.42 ± 0.02 eV at 14.0 GPa and a positive pressure coefficient. Above 18 GPa, the absorption edge becomes structureless and its form seems to be that of an indirect gap. In the downstroke, the same sequence of changes is observed, with a hysteresis of about 4 GPa, confirming the structural nature of the transitions. These results are interpreted in the light of theoretical ab initio band structure calculations.

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Section: Discussionmentioning

confidence: 99%

Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Gilliland

Pellicer‐Porres

Segura

et al. 2006

Physica Status Solidi (b)

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“…(2) predicts an increase of the linewidth with pressure, since the reduced effective mass µ of the exciton is proportional to the gap energy, i.e. PL ( ) E P [13]. Such pressure-induced broadening, however, is too small ( 1 ª meV) to be detected in the pressure range of our experiments.…”

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confidence: 65%

Photoluminescence of CdSe quantum dots with Zn_0.38Cd_0.23Mg_0.39Se barriers under hydrostatic pressure

Reparaz

Goñi

Alonso

et al. 2006

Physica Status Solidi (b)

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We have investigated the pressure dependence of the room-temperature photoluminescence (PL) of selfassembled CdSe quantum dots (QDs) with quaternary ZnCdMgSe barriers. Four samples with different CdSe deposition times, i.e. different average dot size, were studied. Samples exhibit a very distinct emission energy covering the visible spectrum from the red to the blue. We found, however, a similar pressure coefficient of around 47 meV/GPa for the PL emission of all samples. This value is close to that of bulk CdSe, which gives evidence that dot and quaternary barrier material have a similar compressibility. In contrast, the PL linewidth displays a clear trend with respect to the emission energy, the PL line being broader for the smaller dots emitting in the blue. This is explained by taking into account the huge bandgap offset of ≈ 1 eV between dot and barrier and considering quantum confinement effects within a very simplistic infinitely deep square-well model.

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“…3 (a) we show the absorption edge of our wurtzite-type Mg 0.3 Zn 0.7 O thin film as grown on c-oriented ScAlMgO 4 with a thickness of 150 nm. Although the presence of the excitonic absorption indicates the high crystalline quality of the sample, the low-energy absorption tail is clear when we compare the experimental data with the calculated absorption edge according to the Elliot-Toyozawa's theory [24][25][26] considering a single absorption edge [ Fig. 3 (b)].…”

Section: Resultsmentioning

confidence: 99%

Phase segregation in MgxZn1–xO probed by optical absorption and photoluminescence at high pressure

Marín-Borrás

Ruiz‐Fuertes

Segura

et al. 2017

Journal of Applied Physics

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The appearance of segregated wurtzite MgxZn1−xO with low Mg content in thin films with x > 0.3 affected by phase separation, cannot be reliably probed with crystallographic techniques owing to its embedded nanocrystalline configuration. Here we show a high-pressure approach which exploits the distinctive behaviors under pressure of wurtzite MgxZn1−xO thin films with different Mg contents to unveil phase segregation for x > 0.3. By using ambient conditions photoluminescence (PL), and with optical absorption and PL under high pressure for x = 0.3 we show that the appearance of a segregated wurtzite phase with a magnesium content of x ∼ 0.1 is inherent to the wurtzite and rocksalt phase separation. We also show that the presence of segregated wurtzite phase in oversaturated thin films phase is responsible for the low-energy absorption tail observed above x = 0.3 in our MgxZn1−xO thin films. Our study has also allowed us to extend the concentration dependence of the pressure coefficient of the band gap from the previous limit of x = 0.13 to x ≈ 0.3 obtaining dEg/dP = 29 meV/GPa for wurtzite with x ≈ 0.3 and 25 meV/GPa for the segregated x ≈ 0.09 wurtzite phase.

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Effect of pressure on the low-temperature exciton absorption in GaAs

Cited by 134 publications

References 34 publications

Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Photoluminescence of CdSe quantum dots with Zn_0.38Cd_0.23Mg_0.39Se barriers under hydrostatic pressure

Phase segregation in MgxZn1–xO probed by optical absorption and photoluminescence at high pressure

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Effect of pressure on the low-temperature exciton absorption in GaAs

Cited by 134 publications

References 34 publications

Electronic structure of CuAlO2 and CuScO2 delafossites under pressure

Electronic structure of CuAlO2 and CuScO2 delafossites under pressure

Photoluminescence of CdSe quantum dots with Zn0.38Cd0.23Mg0.39Se barriers under hydrostatic pressure

Phase segregation in MgxZn1–xO probed by optical absorption and photoluminescence at high pressure

Contact Info

Product

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Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Electronic structure of CuAlO₂ and CuScO₂ delafossites under pressure

Photoluminescence of CdSe quantum dots with Zn_0.38Cd_0.23Mg_0.39Se barriers under hydrostatic pressure