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GROWTH AND PROPERTIES OF STACKED SELF-ASSEMBLED IN0.5GA0.5AS QUANTUM DOTS Aryanto, Didik; Othaman, Zulkafli; Ismail, Abd. Khamim
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol 2, No 1 (2012)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v2n1.p1-6

Abstract

Self-assembled In0.5Ga0.5As quantum dots (QDs) were grown using metal-organic chemical vapor deposition (MOCVD) on GaAs (100) substrate with different number of stacking QDs layers. Surface study using atomic force microscopy (AFM) shows that surface morphology of the self-assembled QDs change with different number of stacking QDs layers caused by the previous QDs layers and the thickness of the GaAs spacer layers. PL measurement shows variation in the PL spectra as a function of number of stacking layers of In0.5Ga0.5As QDs. The PL peak positions blue-shifted from 1225 nm to 1095 nm and dramatically increase in intensity with increasing number of stacking QDs layers.
GROWTH AND PROPERTIES OF STACKED SELF-ASSEMBLED In0.5Ga0.5As QUANTUM DOTS Aryanto, Didik; Othaman, Zulkafli; Ismail, Abd. Khamim
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol 2, No 1 (2012)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v2n1.p1-6

Abstract

Self-assembled In0.5Ga0.5As quantum dots (QDs) were grown using metal-organic chemical vapor deposition (MOCVD) on GaAs (100) substrate with different number of stacking QDs layers. Surface study using atomic force microscopy (AFM) shows that surface morphology of the self-assembled QDs change with different number of stacking QDs layers caused by the previous QDs layers and the thickness of the GaAs spacer layers. PL measurement shows variation in the PL spectra as a function of number of stacking layers of In0.5Ga0.5As QDs. The PL peak positions blue-shifted from 1225 nm to 1095 nm and dramatically increase in intensity with increasing number of stacking QDs layers.
Estimation of crystallite size, density, and compositional of the Ti: Al2O3 single crystal Kusuma, Hamdan Hadi; Ibrahim, Zuhairi; Othaman, Zulkafli
Jurnal Ilmiah Pendidikan Fisika Al-Biruni Vol 9 No 2 (2020): Jurnal Ilmiah Pendidikan Fisika Al-Biruni
Publisher : Universitas Islam Negeri Raden Intan Lampung, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24042/jipfalbiruni.v9i2.7207

Abstract

The purposes of this research were to estimate the crystallite size, density, and chemical composition of the ingot Ti: Al2O3  crystal grown by the Czochralski method. The crystallite size and composition of Ti: Al2O3 crystals had been determined using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDXS). Based on the Archimedes principle, the density of the crystals had been determined. The XRD patterns showed a single central peak with high intensity for all samples. It indicated that all samples had a single crystal. The average value of the samples' crystallite size was in the range of 20.798 nm to 34.294 nm. The ingot crystal density and Ti composition increased from the top to the bottom part because the solid solution was distributed unevenly during the growth process.