Photoluminescence, Reflectance, and Magnetospectroscopy of Shallow Excitons in GaN

1996 ◽  
Vol 449 ◽  
Author(s):  
B. J. Skromme ◽  
H. Zhao ◽  
B. Goldenberg ◽  
H. S. Kong ◽  
M. T. Leonard ◽  
...  
Keyword(s):  
Binding Energy ◽  
Molecular Beam ◽  
Free Exciton ◽  
Chemical Vapor ◽  
Exciton Binding Energy ◽  
Exciton Peak ◽  
Neutral Donor ◽  
Gas Source ◽  
Donor Binding Energy ◽  
First Time

ABSTRACTWe report several new aspects of the excitonic properties of heteroepitaxial GaN grown on sapphire or 6H-SiC. In particular, we observed the n = 2 free exciton associated with both A and B excitons (which are distinct from the n = 1 C exciton) using reflectance and 1.7 K photoluminescence. We also studied the behavior of the n = 2 A-exciton using magnetoluminescence in fields up to 12 T. The large diamagnetic shift and splitting positively confirm the identification, yielding an exciton binding energy of about 26.4 meV. Several previous identifications of the n = 2 free exciton yielding a smaller exciton binding energy are probably in error, based on our results. We have also detected the two-electron replica of the neutral donor-bound exciton for the first time in GaN and observed its splitting pattern in magnetic fields up to 12 T. This feature is 22 meV below the principal neutral donor-bound exciton peak, independently of strain shifts in the overall spectrum. It yields a precise donor binding energy of 29 meV for the shallow residual donor in material grown by metalorganic chemical vapor deposition and gas-source molecular beam epitaxy, considerably smaller than that of the residual donor reported earlier in hydride vapor phase epitaxial material (about 35.5 meV).

Magnetoluminescence and Resonant Electronic Raman Scattering Investigation of Donors and Excitons in Hydride Vpe and Mocvd GaN

1997 ◽  
Vol 482 ◽  
Author(s):  
B. J. Skromme ◽  
J. Jayapalan ◽  
D. Wang ◽  
O. F. Sankey
Keyword(s):  
Binding Energy ◽  
Raman Scattering ◽  
Free Exciton ◽  
Chemical Vapor ◽  
Hydride Vapor Phase Epitaxy ◽  
Neutral Donor ◽  
Electronic Raman Scattering ◽  
Si Doped ◽  
Nonperturbative Theory ◽  
Donor Species

AbstractThe donor and exciton states in ultra high-quality heteroepitaxial GaN grown by hydride vapor phase epitaxy (HVPE) and metalorganic chemical vapor deposition (MOCVD) on sapphire substrates are investigated using low temperature photoluminescence (PL), reflectance, magnetospectroscopy in fields up to 12 T, and resonant electronic Raman scattering (RERS). The A free exciton is confirmed to have a binding energy of about 26.4 meV, independent of strain in the material. Bound n=2 exciton peaks are distinguished in the PL spectrum by their thermalization and sample dependence. The Si donor is shown to have a binding energy of about 21 meV using Si-doped HVPE samples grown at Epitronics. Up to five additional residual donor species are observed when comparing various HVPE and MOCVD samples. Pronounced temperaturedependence of the two-electron satellites is observed, suggesting the existence of unresolved excited rotator states of the neutral donor-bound exciton. Highly resolved magnetic splitting patterns are observed in the two-electron satellites. A nonperturbative theory of these donor splittings is developed, including anisotropy. Resonant electronic Raman scattering from residual donors is reported, and yields improved linewidths compared to PL.

Ferromagnetic and Paramagnetic Semiconductors Based upon GaN, AlGaN, and GaP

2001 ◽  
Vol 690 ◽  
Author(s):  
Mark E. Overberg ◽  
Gerald T. Thaler ◽  
Rachel M. Frazier ◽  
Brent P. Gila ◽  
Cammy R. Abernathy ◽  
...  
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Hysteretic Behavior ◽  
Ferromagnetic Semiconductors ◽  
Temperature Dependent ◽  
Paramagnetic Behavior ◽  
Gas Source ◽  
P Type ◽  
First Time ◽  
Temperature Dependent Magnetization

ABSTRACTEpitaxial growth of the ferromagnetic semiconductors GaMnP:C and GaMnN has been investigated by Gas Source Molecular Beam Epitaxy (GSMBE). GaMnP:C films grown with 9.4% Mn are found to be p-type with hysteretic behavior to room temperature. GaMnN films grown at 700 °C with 2.8% Mn show hysteresis at 300 K, while temperature-dependent magnetization measurements indicate that the magnetism may persist to much higher temperatures (> 325 K). Samples of AlGaMnN have also been prepared for the first time that show improved surface morphology compared to GaMnN but which show only paramagnetic behavior.

Nanocrystalline Silicon for Optoelectronic Applications

MRS Bulletin ◽  
1998 ◽  
Vol 23 (4) ◽  
pp. 33-38 ◽  
Author(s):  
Leonid Tsybeskov
Keyword(s):  
Binding Energy ◽  
Light Emission ◽  
Crystalline Silicon ◽  
Free Exciton ◽  
Nanocrystalline Silicon ◽  
Momentum Conservation ◽  
Exciton Binding Energy ◽  
Electron Hole ◽  
Energy Plus ◽  
Hole Recombination

Light emission in silicon has been intensively investigated since the 1950s when crystalline silicon (c-Si) was recognized as the dominant material in microelectronics. Silicon is an indirect-bandgap semiconductor and momentum conservation requires phonon assistance in radiative electron-hole recombination (Figure 1a, top left). Because phonons carry a momentum and an energy, the typical signature of phonon-assisted recombination is several peaks in the photoluminescence (PL) spectra at low temperature. These PL peaks are called “phonon replicas.” High-purity c-Si PL is caused by free-exciton self-annihilation with the exciton binding energy of ~11 meV. The TO-phonon contribution in conservation processes is most significant, and the main PL peak (~1.1 eV) is shifted from the bandgap value (~1.17 eV) by ~70 meV—that is, the exciton binding energy plus TO-phonon energy (Figure 1a).

Deposition of Zinc Oxide Thin Films Using a Surface Reaction on Platinum Nanoparticles

2011 ◽  
Vol 1315 ◽  
Author(s):  
Kanji Yasui ◽  
Hitoshi Miura ◽  
Hiroshi Nishiyama
Keyword(s):  
Free Exciton ◽  
Exothermic Reaction ◽  
Chemical Vapor ◽  
Band Edge ◽  
Chemical Vapor Deposition Method ◽  
Zno Films ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Neutral Donor ◽  
Pl Spectra

ABSTRACTA new chemical vapor deposition method for the growth of ZnO films using the reaction between dimethylzinc (DMZn) and thermally excited H2O produced by a Pt-catalyzed H2–O2 reaction was investigated. The thermally excited H2O molecules formed by the exothermic reaction of H2 and O2 on the catalyst were ejected from a fine nozzle into the reaction zone and allowed to collide with DMZn ejected from another fine nozzle. The ZnO films were grown directly on a-plane (11-20) sapphire substrates at substrate temperatures of 773-873 K with no buffer layer. X-ray diffraction patterns exhibited intense (0002) and (0004) peaks from the ZnO(0001) index plane. The smallest full width at half maximum (FWHM) value of the ω- rocking curve of ZnO(0002) was less than 0.1º. The largest Hall mobility and the smallest residual carrier concentration of the ZnO films were 169 cm2V−1s−1 and 1.7×1017 cm−3, respectively. Photoluminescence (PL) spectra at room temperature exhibited a band edge emission at 3.29 eV, with a FWHM of 104 meV. Green luminescence from deeper levels was generally about 1.5% of the band edge emission intensity. PL spectra at 5 K showed a strong emission peak at 3.3603 eV, attributed to the neutral donor-bound exciton Dºx. The FWHM was as low as 1.0 meV. Free exciton emissions also appeared at 3.3757 eV (FXA, n=1) and 3.4221 eV (FXA, n=2).

Growth and Characterization of BRS GaInAsp-GaAs Laser Emitting At 0.8μm by Gas-Source Molecular Beam Epitaxy

1995 ◽  
Vol 417 ◽  
Author(s):  
C. Jelen ◽  
S. Slivken ◽  
J. Diaz ◽  
M. Erdtmann ◽  
S. Kim ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Molecular Beam ◽  
Laser System ◽  
Chemical Vapor ◽  
Ridge Structure ◽  
Gas Source ◽  
Gaas Laser

AbstractGaInAsP-GaAs buried ridge structure lasers emitting at 0.8μm have been fabricated on material grown in two steps by low pressure metalorganic chemical vapor deposition and gas-source molecular beam epitaxy. Preliminary laser results are reported, and the feasibility of using gas-source molecular beam epitaxy for the regrowth of sophisticated laser system is demonstrated.

Intrinsic Photoconductivity of 6H-SiC and the Free-Exciton Binding Energy

2001 ◽  
Vol 353-356 ◽  
pp. 405-408 ◽  
Author(s):  
Ivan G. Ivanov ◽  
T. Egilsson ◽  
Jie Zhang ◽  
Alexsandre Ellison ◽  
Erik Janzén
Keyword(s):  
Binding Energy ◽  
Free Exciton ◽  
Exciton Binding Energy
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