Doping of InP Quantum Dots and Its Optical Properties

doi:10.15541/jim20160212

Abstract

Abstract:

The Li⁺ and Zn²⁺ doped InP quantum dots (denoted as Li: InP QDs and Zn: InP QDs) were synthesized via an in-situ nucleation doping approach. Effects of dopant on the structure, size and optical property of QDs were investigated in detail. The results showed that Li: InP and Zn: InP QDs were well crystallized with uniform size. In the case of Li⁺ dopant, Li⁺ did not enter the InP lattice, but inhibited the nucleation and growth of InP QDs. Blue shifts were observed in UV-Vis absorption spectra and fluorescence spectra due to the quantum size effect of Li: InP QDs. Compared with Li⁺, Zn²⁺ dopant also inhibited nucleation and growth of InP QDs, but InP/Zn₃P₂/ZnO composite was produced with a core-shell structure, resulted in a great improvement of photoluminescence (PL) intensity. Especially when the doping concentration of Zn/In atomic ratio was 0.2, the PL intensity was increased more than 100 times as compared with that of undoped InP QDs. This work may provide a considerable approach to the synthesis of short-wavelength InP QDs.

Key words: InP, quantum dot, doping, optical-property

CLC Number:

TL812

YANG Suo-Long, WANG Xiao-Fang, JIANG Chun-Li, ZHAO Ya-Wen, ZENG Rong-Guang, WANG Huai-Sheng, LAI Xin-Chun. Doping of InP Quantum Dots and Its Optical Properties[J]. Journal of Inorganic Materials, 2016, 31(10): 1051-1057.

Figures/Tables 7

Fig. 1 Evolution absorption spectra of (a) Li: InP and (b) Zn: InP QDs. Absorption spectra of (c) Li: InP QDs and (d) Zn: InP QDs with different dopant contents

Table 1 Calculated D and Eg of Li: InP and Zn: InP QDs

Sample	Peak/nm	D/nm	E_g/eV	Sample	Peak/nm	D/nm	E_g/eV
Undoped	564	2.91	2.20	Undoped	564	2.91	2.20
Zn/In=0.1	534	2.55	2.32	Li/In=0.1	520	2.40	2.38
Zn/In=0.2	518	2.38	2.39	Li/In=0.2	499	2.20	2.48
Zn/In=0.3	491	2.13	2.53	Li/In=0.3	495	2.16	2.51

Fig. 2 TEM images of undoped InP QDs, Li: InP QDs and Zn: InP QDs QDs The insets are the corresponding HRTEM images (a-c) and size distribufion (a-e) (a) undoped InP QDs, (b) Li: InP QDs with Li/In=0.1, Zn: InP QDs QDs with (c) Zn/In=0.1 (d) Zn/In=0.2, (e) Zn/In=0.3

Fig. 3 XRD patterns of undoped InP, Li: InP and Zn: InP QDs

Fig. 4 XPS spectra of Zn: InP QDs (a) P2p; (b) In3d; (c) Zn2p; (d) Survey spectra

Fig. 5 XPS spectra of Li: InP QDs (a) P2p; (b) In3d; (c) Li1s; (d) Survey spectra

Fig. 6 PL spectra of (a) Li: InP and (b) Zn: InP QDs with various dopant concentration

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