PHOTOLUMINESCENCE OF ULTRA SMALL InAs/GaAs QUANTUM DOTS

2005 ◽  
Vol 19 (18) ◽  
pp. 907-917 ◽  
Author(s):  
Y. G. LIN ◽  
C. H. WU ◽  
S. L. TYAN ◽  
S. D. LIN ◽  
C. P. LEE

The InAs/GaAs quantum dots (QDs) with a baselength of less than 10 nm are studied by the excitation-, temperature-dependent and magneto-photoluminescence (PL). The baselengths of the QDs, calculated by the PL ground state transition energy and estimated by magneto-PL spectra, are in agreement with the result of atomic force microscopy measurements. By means of the excitation-dependent PL, we demonstrate that only the ground electron and hole states exist when the baselength of the QDs is smaller than about 7.3 nm, whereas the larger dots with a baselength of about 8.7 nm will give rise to one excited hole state. The measured energy separation between the ground and the excited hole states is in good agreement with the theoretical calculation. The transition energy in temperature-dependent PL spectra shows a rapid redshift as the temperature is higher than the critical temperature. The redshift rate is about 2.8 and 2.5 times larger than the values calculated by Varshni's law for small and large dots respectively. The higher redshift rate can be explained by the stronger tunneling effect. In addition, the PL linewidths show a V-shape dependence with the temperature. This behavior could be well described as a tunneling and electron-phonon scattering effect.

2020 ◽  
Vol 10 (3) ◽  
pp. 283-290
Author(s):  
Guodong Wang ◽  
Zengguang Liu ◽  
Junjun Wang ◽  
Yingli Yang ◽  
Xiaolian Liu ◽  
...  

AbstractA detailed analysis of the electrical response of In0.3Ga0.7As surface quantum dots (SQDs) coupled to 5-layer buried quantum dots (BQDs) is carried out as a function of ethanol and acetone concentration while temperature-dependent photoluminescence (PL) spectra are also analyzed. The coupling structure is grown by solid source molecular beam epitaxy. Carrier transport from BQDs to SQDs is confirmed by the temperature-dependent PL spectra. The importance of the surface states for the sensing application is once more highlighted. The results show that not only the exposure to the target gas but also the illumination affect the electrical response of the coupling sample strongly. In the ethanol atmosphere and under the illumination, the sheet resistance of the coupling structure decays by 50% while it remains nearly constant for the reference structure with only the 5-layer BQDs but not the SQDs. The strong dependence of the electrical response on the gas concentration makes SQDs very suitable for the development of integrated micrometer-sized gas sensor devices.


2002 ◽  
Vol 81 (9) ◽  
pp. 1621-1623 ◽  
Author(s):  
Y. Q. Wei ◽  
S. M. Wang ◽  
F. Ferdos ◽  
J. Vukusic ◽  
A. Larsson ◽  
...  

2015 ◽  
Vol 6 (14) ◽  
pp. 2841-2846 ◽  
Author(s):  
Kenneth O. Aruda ◽  
Miriam Bohlmann Kunz ◽  
Mario Tagliazucchi ◽  
Emily A. Weiss

2008 ◽  
Vol 55-57 ◽  
pp. 493-496
Author(s):  
Wisanu Pecharapa ◽  
P. Potirak ◽  
W. Yindeesuk

II-VI inorganic/organic heterostructures consisting of ZnSe and tris(8-hydroxyquinoline) aluminum (Alq3) were prepared by electron beam evaporator. Alq3 layer with 20 nm was grown between 200-nm ZnSe layers. Photoluminescence measurement was conducted at various temperatures in order to investigate the important temperature-dependent parameters of this structure. PL spectra revealed thermal population of exciton state and the change in PL quantum efficiency of the film.


2012 ◽  
Vol 482-484 ◽  
pp. 2547-2550
Author(s):  
Peng Fei Gu ◽  
Ya Nan Wang ◽  
Jia Jia Cao ◽  
Yu Yan ◽  
Tie Qiang Zhang ◽  
...  

We here report the temperature effect on photoluminescence(PL) spectra of PbSe quantum dots (QDs), which exhibit a strong temperature dependence on their spectra position and intensity. They potentially act as the temperature marker, sensing temperature variations and reporting temperature changes remotely through optical readout. In addition, the temperature sensitivity characterized by peak position of PbSe QDs was found to be 0.39nm/°C in a range of 10-100 °C.


2021 ◽  
Vol 119 (7) ◽  
pp. 073303
Author(s):  
Jialin Wu ◽  
Lixiang Chen ◽  
Yongshuang Zhao ◽  
Zuhong Xiong ◽  
Wenyu Ji ◽  
...  

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