Please wait a minute...
Chin. Phys. B, 2015, Vol. 24(2): 028103    DOI: 10.1088/1674-1056/24/2/028103

Effects of annealing temperature on shape transformation and optical properties of germanium quantum dots

Alireza Samavatia, Z. Othamana, S. K. Ghoshalb, M. K. Mustafac
a Ibn Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia;
b Advanced Optical Material Research Group, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Malaysia;
c Faculty of Science Technology and Human Development, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Johor, Malaysia
Abstract  The influences of thermal annealing on the structural and optical features of radio frequency (rf) magnetron sputtered self-assembled Ge quantum dots (QDs) on Si (100) are investigated. Preferentially oriented structures of Ge along the (220) and (111) directions together with peak shift and reduced strain (4.9% to 2.7%) due to post-annealing at 650 ℃ are discerned from x-ray differaction (XRD) measurement. Atomic force microscopy (AFM) images for both pre-annealed and post-annealed (650 ℃) samples reveal pyramidal-shaped QDs (density ~ 0.26×1011 cm-2) and dome-shape morphologies with relatively high density ~ 0.92 ×1011 cm-2, respectively. This shape transformation is attributed to the mechanism of inter-diffusion of Si in Ge interfacial intermixing and strain non-uniformity. The annealing temperature assisted QDs structural evolution is explained using the theory of nucleation and growth kinetics where free energy minimization plays a pivotal role. The observed red-shift ~ 0.05 eV in addition to the narrowing of the photoluminescence peaks results from thermal annealing, and is related to the effect of quantum confinement. Furthermore, the appearance of a blue-violet emission peak is ascribed to the recombination of the localized electrons in the Ge-QDs/SiO2 or GeOx and holes in the ground state of Ge dots. Raman spectra of both samples exhibit an intense Ge-Ge optical phonon mode which shifts towards higher frequency compared with those of the bulk counterpart. An experimental Raman profile is fitted to the models of phonon confinement and size distribution combined with phonon confinement to estimate the mean dot sizes. A correlation between thermal annealing and modifications of the structural and optical behavior of Ge QDs is established. Tunable growth of Ge QDs with superior properties suitable for optoelectronic applications is demonstrated.
Keywords:  Ge QDs      sputtering      surface morphology      optical properties     
Received:  22 June 2014      Published:  05 February 2015
PACS:  81.10.Pq (Growth in vacuum)  
  78.67.Hc (Quantum dots)  
  81.16.Dn (Self-assembly)  
Fund: Project supported by Ibnu Sina Institute for Fundamental Science Study, Universiti Teknologi Malaysia through Vote Q.J130000.2526.02H94, O5 and Postdoctoral Research Grant.
Corresponding Authors:  Alireza Samavati     E-mail:

Cite this article: 

Alireza Samavati, Z. Othaman, S. K. Ghoshal, M. K. Mustafa Effects of annealing temperature on shape transformation and optical properties of germanium quantum dots 2015 Chin. Phys. B 24 028103

[1] Yang J, Jin Y, Wang C, Li L, Tao D and Yang Y 2012 Appl. Surf. Sci. 258 3637
[2] Kolobov A V 2000 J. Appl. Phys. 87 2926
[3] Das K, Goswami M L N, Dhar A, Mathur B K and Ray S K 2007 Nanotechnology 18 175301
[4] Yoffe D 2001 Adv. Phys. 50 1
[5] Ledentsov N N, Ustinov V M, Shchukin V A, Kopev P S, Alferov Z A and Bimberg D 1998 Semiconductors 32 343
[6] Alguno A, Usami N, Ujihara T, Fujiwara K, Sazaki G, Nakajima K and Shiraki Y 2003 Appl. Phys. Lett. 83 1258
[7] Zhang Y and Drucker J 2003 J. Appl. Phys. 93 15
[8] Saito H, Nishi K and Sugou S 1999 Appl. Phys. Lett. 74 1224
[9] Mukhametzhanov I, Wei Z, Heitz R and Madhukar A 1999 Appl. Phys. Lett. 75 85
[10] Stangl J, Holy V and Bauer G 2004 Rev. Mod. Phys. 76 725
[11] Biasiol G and Heun S 2011 Phys. Rep. 500 117
[12] Li C, Xu J, Li W, Jiang X F, Sun S H, Xu L and Chen K J 2013 Chin. Phys. B 22 107201
[13] Samavati A R, Othaman Z, Dabagh S and Ghoshal S K 2014 J. Nanosci. Nanotechnol. 14 5266
[14] Samavati A R, Othaman Z, Ghoshal S K and Amjad R J 2013 Chin. Phys. B 22 098102
[15] Prokes S M, Glembocki O J and Godbey D J 1992 Appl. Phys. Lett. 60 1087
[16] Tersoff J and LeGoues F K 1994 Phys. Rev. Lett. 72 3570
[17] Chen Y and Washburn J 1996 Phys. Rev. Lett. 77 4046
[18] Jesson D E, Chen G, Chen K M and Pennycook S J 1998 Phys. Rev. Lett. 80 5156
[19] Daruka I and Barabasi A L 1997 Phys. Rev. Lett. 79 3708
[20] Ross F M, Tersoff J and Tromp R M 1998 Phys. Rev. Lett. 80 984
[21] Cullity B D 1956 Elements of x-ray Diffraction (Massachusetts: Addison-Wesley Publishing Company)
[22] Cohen M L and Chelikowsky J R 1989 Electronic Structure and Optical Properties of Semiconductors, in Springer Series Solid-State Science, 2nd edn. (Berlin: Springer-Verlag)
[23] Min K S, Shcheglov K V, Yang C M, Atwater H A, Brongersma M L and Polman A 1996 Appl. Phys. Lett. 68 2511
[24] Takeoka S, Fujii M, Hayashi S and Yamamoto K 1998 Phys. Rev. B 58 7921
[25] Kartopu G, Karavanski V A, Serincan U, Turan R, Hummel R E, Ekinci Y, Gunnaes A and Fin-stad T G 2005 Phys. Stat. Sol. A 202 1472
[26] Huang Z H, Liang S D, Chen C Y and Lin D L 1998 J. Phys: Condens. Matter 10 1985
[27] Liu J L, Jin G, Tang Y S, Luo Y H, Wang K L and Yu D P 2000 Appl. Phys. Lett. 76 586
[28] Samavati A R, Othaman Z, Ghoshal S K and Dousti M R 2014 J. Lumin. 154 51
[29] Samavati A R, Othaman Z, Ghoshal S K and Zare S 2013 Chin. Opt. Lett. 11 112502
[30] P M Fauchett and Campbell I H 1988 Crit. Rev. Solid State Mater. 14 S14
[1] Influence of CdS films synthesized by different methods on the photovoltaic performance of CdTe/CdS thin film solar cells
Jun Wang(汪俊), Yuquan Wang(王玉全), Cong Liu(刘聪), Meiling Sun(孙美玲), Cao Wang(王操), Guangchao Yin(尹广超), Fuchao Jia(贾福超), Yannan Mu(牟艳男), Xiaolin Liu(刘笑林), Haibin Yang(杨海滨). Chin. Phys. B, 2020, 29(9): 098802.
[2] Structural and optical characteristic features of RF sputtered CdS/ZnO thin films
Ateyyah M Al-Baradi, Fatimah A Altowairqi, A A Atta, Ali Badawi, Saud A Algarni, Abdulraheem S A Almalki, A M Hassanien, A Alodhayb, A M Kamal, M M El-Nahass. Chin. Phys. B, 2020, 29(8): 080702.
[3] Effects of built-in electric field and donor impurity on linear and nonlinear optical properties of wurtzite InxGa1-xN/GaN nanostructures
Xiao-Chen Yang(杨晓晨), Yan Xing(邢雁). Chin. Phys. B, 2020, 29(8): 087802.
[4] Influence of N+ implantation on structure, morphology, and corrosion behavior of Al in NaCl solution
Hadi Savaloni, Rezvan Karami, Helma Sadat Bahari, Fateme Abdi. Chin. Phys. B, 2020, 29(5): 058102.
[5] Ab initio study of structural, electronic, thermo-elastic and optical properties of Pt3Zr intermetallic compound
Wahiba Metiri, Khaled Cheikh. Chin. Phys. B, 2020, 29(4): 047101.
[6] Improvement of high-frequency properties of Co2FeSi Heusler films by ultrathin Ru underlayer
Cuiling Wang(王翠玲), Shouheng Zhang(张守珩), Shandong Li(李山东), Honglei Du(杜洪磊), Guoxia Zhao(赵国霞), Derang Cao(曹德让). Chin. Phys. B, 2020, 29(4): 046202.
[7] Low-temperature plasma enhanced atomic layer deposition of large area HfS2 nanocrystal thin films
Ailing Chang(常爱玲), Yichen Mao(毛亦琛), Zhiwei Huang(黄志伟), Haiyang Hong(洪海洋), Jianfang Xu(徐剑芳), Wei Huang(黄巍), Songyan Chen(陈松岩), Cheng Li(李成). Chin. Phys. B, 2020, 29(3): 038102.
[8] Influences of grain size and microstructure on optical properties of microcrystalline diamond films
Jia-Le Wang(王家乐), Cheng-Ke Chen(陈成克), Xiao Li(李晓), Mei-Yan Jiang(蒋梅燕), Xiao-Jun Hu(胡晓君). Chin. Phys. B, 2020, 29(1): 018103.
[9] Optical and electrical properties of InGaZnON thin films
Jian Ke Yao(姚建可), Fan Ye(叶凡), Ping Fan(范平). Chin. Phys. B, 2020, 29(1): 018105.
[10] High-throughput fabrication and semi-automated characterization of oxide thin film transistors
Yanbing Han(韩炎兵), Sage Bauers, Qun Zhang(张群), Andriy Zakutayev. Chin. Phys. B, 2020, 29(1): 018502.
[11] Electronic and optical properties of GaN-MoS2 heterostructure from first-principles calculations
Dahua Ren(任达华), Xingyi Tan(谭兴毅), Teng Zhang(张腾), Yuan Zhang(张源). Chin. Phys. B, 2019, 28(8): 086104.
[12] Quantum density functional theory studies of structural, elastic, and opto-electronic properties of ZMoO3 (Z=Ba and Sr) under pressure
Saad Tariq, A A Mubarak, Saher Saad, M Imran Jamil, S M Sohail Gilani. Chin. Phys. B, 2019, 28(6): 066101.
[13] Interlayer distance effects on absorption coefficient and refraction index change in p-type double-δ-doped GaAs quantum wells
H Noverola-Gamas, L M Gaggero-Sager, O Oubram. Chin. Phys. B, 2019, 28(12): 124207.
[14] Effect of flash thermal annealing by pulsed current on rotational anisotropy in exchange-biased NiFe/FeMn film
Zhen Wang(王振), Shi-Jie Tan(谭士杰), Jun Li(李俊), Bo Dai(代波), Yan-Ke Zou(邹延珂). Chin. Phys. B, 2018, 27(8): 087504.
[15] Effect of pressure on the elastic properties and optoelectronic behavior of Zn4B6O13: First-principles investigation
Pei-Da Wang(王培达), Zhen-Yuan Jia(贾镇源), Yu-Han Zhong(钟玉菡), Hua-Yue Mei(梅华悦), Chun-Mei Li(李春梅), Nan-Pu Cheng(程南璞). Chin. Phys. B, 2018, 27(5): 057101.
No Suggested Reading articles found!