Atomic Force Microscopy and Spectroscopy of Self-Assembled InAsSb Quantum Dots grown on InP Substrates by MOCVD

2004 ◽  
Vol 829 ◽  
Author(s):  
Yongkun Sin ◽  
Hyun I. Kim ◽  
Gary W. Stupian ◽  
Yueming Qiu

ABSTRACTInAsSb quantum dot (QD) lasers are promising light sources with emission wavelengths beyond 2μm as recently demonstrated. We report the first detailed atomic force microscope (AFM) characterization of uncapped InAsSb quantum dots self-assembled on GaAs/In0.53Ga0.47As layers. These quantum dot structures are grown on (100) InP substrates by metal organic chemical vapor deposition (MOCVD). Growth conditions are chosen to maximize photoluminescence intensity and to obtain high output powers from Fabry-Perot lasers with one stack of InAsSb QDs. Conductive AFM is employed to simultaneously study topography, current image, and current-voltage (I-V) characteristics from various InAs1-ySby QDs with y varied between 0 and 0.25. Typical dot density is 4–5×1010/cm2 and dots are estimated to have a lateral dimension at the base of ∼40nm and a height of 2–5nm. I-V characteristics measured from individual InAsSb QDs are compared to those from InAs QDs. Also reported are electronic properties including energy band gaps of InAs and InAsSb QDs.

2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Didik Aryanto ◽  
Zulkafli Othaman ◽  
Abd. Khamim Ismail

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.


2014 ◽  
Vol 896 ◽  
pp. 215-218
Author(s):  
Didik Aryanto ◽  
Zulkafli Othaman ◽  
A. Khamim Ismail

Stacked self-assembled In0.5Ga0.5As/GaAs quantum dots (QDs) were grown using metal organic chemical vapor deposition (MOCVD). Atomic force microscopy (AFM), transmission electron microscopy (TEM) and high resolution X-ray diffraction (HR-XDR) show the effects of stacking on morphology and structure of QDs. Strains due to the buried QDs affect the shape and alignment of the successive layers. Capping of these QDs also determine the quality of the top most QDs structure.


1997 ◽  
Vol 482 ◽  
Author(s):  
H. Hirayama ◽  
S. Tanaka ◽  
P. Ramvall ◽  
Y. Aoyagi

AbstractWe demonstrate photoluminescence from self- assembling InGaN quantum dots (QDs), which are artificially fabricated on AlGaN surfaces via metal- organic chemical vapor deposition. InGaN QDs are successfully fabricated by the growth mode transition from step- flow to three dimensional island formation by using anti-surfactant silicon on AlGaN surface. The diameter and height of the fabricated InGaN QDs are estimated to be ˜10nm and ˜5nm, respectively, by an atomic- force- microscope (AFM). Indium mole fraction of InxGal−x N QDs is controlled from x=˜0.22 to ˜0.52 by varying the growth temperature of QDs. Intense photoluminescence is observed even at room temperature from InGaN QDs embedded with the GaN capping layers. In addition, the temperature- dependent energy shift of the photoluminescence peak- energy shows a localization behavior.


2005 ◽  
Vol 891 ◽  
Author(s):  
Ronald A. Arif ◽  
Nam-Heon Kim ◽  
Luke J. Mawst ◽  
Nelson Tansu

ABSTRACTSelf-assembled InGaAs quantum dots (QD) grown by metal organic chemical vapor deposition (MOCVD) have a natural peak emission wavelength around 1150-1200-nm due to its specific composition, shapes, and sizes. In this work, a new method to engineer the emission wavelength capability of MOCVD-grown InGaAs QD on GaAs to ∼1000-nm by utilizing interdiffused InGaAsP QD has been demonstrated. Incorporation of phosphorus species from the GaAsP barriers into the MOCVD-grown self-assembled InGaAs QD is achieved by interdiffusion process. Reasonably low threshold characteristics of ∼ 200-280 A/cm2 have been obtained for interdiffused InGaAsP QD lasers emitting at 1040-nm, which corresponds to blue-shift of ∼ 85-90-nm in comparison to that of unannealed InGaAs QD laser.


2012 ◽  
Vol 571 ◽  
pp. 269-272
Author(s):  
Peng Tian ◽  
Chong Qing Huang ◽  
Wen Hua Luo ◽  
Jing Liu

Self-assembled InAs/GaAs quantum dots structures with low temperature and high temperature cap layers are grown by meta-organic chemical vapor deposition. The effects of Indium composition of high temperature InGaAs cap layer on the structural and optical properties of quantum dots are investigated by the atomic force microscopy and photoluminescence. Emission peak wavelengths shift from 1218 nm to 1321 nm when the Indium composition of high temperature InGaAs cap layer increase form 0 to 0.17.


2001 ◽  
Vol 692 ◽  
Author(s):  
R. D. Dupuis ◽  
J. H. Ryou ◽  
R. D. Heller ◽  
G. Walter ◽  
D. A. Kellogg ◽  
...  

AbstractWe describe the operation of lasers having active regions composed of InP selfassembled quantum dots embedded in In0.5Al0.3Ga0.2P grown on GaAs (100) substrates by MOCVD. InP quantum dots grown on In0.5Al0.3Ga0.2P have a high density on the order of about 1–2×10 cm−2 with a dominant size of about 10–15 nm for 7.5 ML growth.[1] These In0.5Al0.3Ga0.2P/InP quantum dots have previously been characterized by atomic-force microscopy, high-resolution transmission electron microscopy, and photoluminescence.[2] We report here the 300K operation of optically pumped red-emitting quantum dots using both double quantum-dot active regions and quantum-dot coupled with InGaP quantum-well active regions. Optically and electrically pumped 300K lasers have been obtained using this active region design; these lasers show improved operation compared to the lasers having QD-based active regions with threshold current densities as low as Jth ∼ 0.5 KA/cm2.


Author(s):  
Qimiao Chen ◽  
Liyao Zhang ◽  
Yuxin Song ◽  
Xiren Chen ◽  
Sebastian Koelling ◽  
...  

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