@article{teng_muth_kolbas_hassan_sharma_kvit_narayan_2000, title={Quantum confinement of E-1 and E-2 transitions in Ge quantum dots embedded in an Al2O3 or an AlN matrix}, volume={76}, ISSN={["0003-6951"]}, DOI={10.1063/1.125650}, abstractNote={Alternating layers of Ge quantum dots embedded in either Al2O3 or AlN matrices were deposited on sapphire substrates by pulsed-laser deposition. The characteristics of the dots are shown to be independent of the surrounding matrix. The dots size (73, 130, 160, and 260 ű5%) was controlled by the laser energy density and deposition time, and was characterized by high-resolution transmission electron microscopy. The dots were single crystalline with no apparent GeOx interfacial layers. Transmission spectroscopy at room temperature and 77 K was used to probe the above-band-edge absorption of the Ge nanodots. The spectral positions of both E1/E1+Δ1 and E2 transitions were found to shift to higher energy in the absorption spectra with decreasing nanodot sizes. This indicates that strong quantum-confinement effect permits the optical properties of Ge dots to be modified in a controlled manner.}, number={1}, journal={APPLIED PHYSICS LETTERS}, author={Teng, CW and Muth, JF and Kolbas, RM and Hassan, KM and Sharma, AK and Kvit, A and Narayan, J}, year={2000}, month={Jan}, pages={43–45} }
 @inproceedings{teng_muth_kolbas_hassan_sharma_narayan_2000, title={Quantum confinement of E1 and E2 transitions in Ge quantum dots embedded in Al203 or an AlN matrix}, booktitle={Optical microstructural characterization of semiconductors  (Materials Research Society proceedings, vol. 588)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Teng, C. W. and Muth, J. F. and Kolbas, R. M. and Hassan, K. M. and Sharma, A. K. and Narayan, J.}, editor={J. Piqueras, T. Sekiguchi and Unlu, M. S.Editors}, year={2000} }
 @inproceedings{hassan_sharma_narayan_muth_teng_kolbas_2000, title={Size effect in germanium nanostructures fabricated by pulsed laser deposition}, booktitle={Nanophase and Nanocomposite Materials III  (Materials Research Society proceedings; vol. 581)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Hassan, K. M. and Sharma, A. K. and Narayan, J. and Muth, J. F. and Teng, C. W. and Kolbas, R. M.}, editor={H. Hahn, S. Komarneni and Parker, J. C.Editors}, year={2000} }
 @article{hassan_sharma_narayan_muth_teng_kolbas_1999, title={Optical and structural studies of Ge nanocrystals embedded in AlN matrix fabricated by pulsed laser deposition}, volume={75}, ISSN={["1077-3118"]}, DOI={10.1063/1.124648}, abstractNote={We have fabricated Ge nanostructures buried in a matrix of AlN grown on Si(111) by pulsed laser deposition at the substrate temperature of 500 °C. The characterization of these structures was performed using high-resolution transmission electron microscopy (HRTEM), photoluminescence, and Raman spectroscopy. The HRTEM results show that the Ge islands are single crystal with a pyramidal shape. The average size of Ge islands was determined to be ∼15 nm, which could be varied by controlling laser deposition and substrate parameters. The Raman spectrum showed a peak of the Ge–Ge vibrational mode downward shifted up to 295 cm−1 which is caused by quantum confinement of phonons in the Ge dots. The photoluminescence of the Ge dots (size ∼15 nm) was blueshifted by ∼0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ∼1.0 eV. The transmission measurements carried out on different samples having Ge dot sizes of 7, 8, and 13 nm deposited on sapphire substrate showed the above band edge transitions of Ge, which were also blueshifted in accordance with the quantum confinement effect. The importance of pulsed laser deposition in fabricating novel nanostructures is emphasized.}, number={9}, journal={APPLIED PHYSICS LETTERS}, author={Hassan, KM and Sharma, AK and Narayan, J and Muth, JF and Teng, CW and Kolbas, RM}, year={1999}, month={Aug}, pages={1222–1224} }
 @inproceedings{teng_muth_kolbas_hassan_sharma_kvit_narayan_1999, title={Quantum confinement of above-band-bap transitions in Ge quantum dots embedded in an Al2O3 or AIN matrix}, booktitle={Optical microstructural characterization of semiconductors  (Materials Research Society proceedings, vol. 588)}, publisher={Pittsburgh, Pa.: Materials Research Society}, author={Teng, C. W. and Muth, J. F. and Kolbas, R. M. and Hassan, K. M. and Sharma, A. K. and Kvit, A. and Narayan, J.}, editor={J. Piqueras, T. Sekiguchi and Unlu, M. S.Editors}, year={1999} }
 @inproceedings{hassan_sharma_narayan_muth_teng_kolbas_1998, title={Germanium nanostructures fabricated by pulsed laser deposition}, booktitle={Microcrystalline and nanocrystalline semiconductors--1998: symposium held November 30-December 3, 1998, Boston, Massachusetts, U.S.A.}, author={Hassan, K. M. and Sharma, A. K. and Narayan, J. and Muth, J. F. and Teng, C. W. and Kolbas, R. M.}, year={1998} }