Effect of scattering by native defects on electron mobility in modulation‐doped heterostructures

1991 ◽  
Vol 58 (15) ◽  
pp. 1638-1640 ◽  
Author(s):  
W. Walukiewicz ◽  
E. E. Haller
1989 ◽  
Vol 163 ◽  
Author(s):  
W. Walukiewicz

AbstractFormation of native defects in GaAs is described in terms of the amphoteric native defect model. It is shown that Fermi energy induced formation of gallium vacancies is responsible for the limitations of maximum free electron concentration in GaAs. The effect of the defects on electron mobility in heavily doped n-GaAs is quantitatively evaluated. Defect scattering explains the abrupt reduction of electron mobility at high doping levels. Also, it is demonstrated that native defects are responsible for the mobility reduction in inverted modulation doped GaAs/AlGaAs heterostructures. The amphoteric defect model also explains a distinct asymmetry in defect formation in n- and p-GaAs. In p-GaAs the Fermi level induced reduction of the defect formation energy is much smaller, and therefore the concentration of the native defects is negligible compared with the hole concentration.


Author(s):  
Chun Yuen HO ◽  
Chia Hsiang Li ◽  
Chao Ping Liu ◽  
Zhi-Quan Huang ◽  
Feng-Chuan Chuang ◽  
...  

Abstract CdO-ZnO alloys (CdxZn1-xO) exhibit a transformation from the wurtzite (WZ) to the rocksalt (RS) phase at a CdO composition of ~70% with a drastic change in the band gap and electrical properties. RS-CdxZn1-xO alloys (x>0.7) are particularly interesting for transparent conductor applications due to their wide band gap and high electron mobility. In this work, we synthesized RS-CdxZn1-xO alloys doped with different concentrations of In dopants and evaluated their electrical and optical properties. Experimental results are analyzed in terms of the amphoteric native defect model and compared directly to defect formation energies obtained by hybrid density functional theory (DFT) calculations. A saturation in electron concentration of ~7x1020cm-3 accompanied by a rapid drop in electron mobility is observed for the RS-CdxZn1-xO films with 0.7≤x<1 when the In dopant concentration [In] is larger than 3%. Hybrid DFT calculations confirm that the formation energy of metal vacancy acceptor defects is significantly lower in RS-CdxZn1-xO than in CdO, and hence limits the free carrier concentration. Mobility calculations reveal that due to the strong compensation by native defects, RS-CdxZn1-xO alloys exhibit a compensation ratio of >0.7 for films with x<0.8. As a consequence of the compensation by native defects, in heavily doped RS-CdxZn1-xO carrier-induced band filling effect is limited. Furthermore, the much lower mobility of the RS-CdxZn1-xO alloys also results in a higher resistivity and reduced transmittance in the near infra-red region (λ>1100 nm), making the material not suitable as transparent conductors for full spectrum photovoltaics.


2011 ◽  
Vol 64 (12) ◽  
pp. 1587 ◽  
Author(s):  
Ahmad Irfan ◽  
Abdullah G. Al-Sehemi ◽  
Shabbir Muhammad ◽  
Jingping Zhang

Theoretically calculated mobility has revealed that BDT is a hole transfer material, which is in good agreement with experimental investigations. The BDT, NHBDT, and OBDT are predicted to be hole transfer materials in the C2/c space group. Comparatively, hole mobility of BHBDT is 7 times while electron mobility is 20 times higher than the BDT. The packing effect for BDT and designed crystals was investigated by various space groups. Generally, mobility increases in BDT and its analogues by changing the packing from space group C2/c to space groups P1 or . In the designed ambipolar material, BHBDT hole mobility has been predicted 0.774 and 3.460 cm2 Vs–1 in space groups P1 and , which is 10 times and 48 times higher than BDT (0.075 and 0.072 cm2 Vs–1 in space groups P1 and ), respectively. Moreover, the BDT behaves as an electron transfer material by changing the packing from the C2/c space group to P1 and .


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4439
Author(s):  
Shui-Yang Lien ◽  
Yu-Hao Chen ◽  
Wen-Ray Chen ◽  
Chuan-Hsi Liu ◽  
Chien-Jung Huang

In this study, adding CsPbI3 quantum dots to organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a doped perovskite film filmed by different temperatures was found to effectively reduce the formation of unsaturated metal Pb. Doping a small amount of CsPbI3 quantum dots could enhance thermal stability and improve surface defects. The electron mobility of the doped film was 2.5 times higher than the pristine film. This was a major breakthrough for inorganic quantum dot doped organic perovskite thin films.


2021 ◽  
Vol 129 (10) ◽  
pp. 105701
Author(s):  
I. Stenger ◽  
M.-A. Pinault-Thaury ◽  
N. Temahuki ◽  
R. Gillet ◽  
S. Temgoua ◽  
...  

2021 ◽  
pp. 108050
Author(s):  
Maria Glória Caño de Andrade ◽  
Luis Felipe de Oliveira Bergamim ◽  
Braz Baptista Júnior ◽  
Carlos Roberto Nogueira ◽  
Fábio Alex da Silva ◽  
...  

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