Pressure dependent photoluminescence study of wurtzite InP nanowires
Supporting Information for
Pressure dependent photoluminescence study of wurtzite InP nanowires N. Chauvin1, A. Mavel1,2, G. Patriarche3, B. Masenelli1, M. Gendry2, D. Machon4. 1
Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, INSA-
Lyon, 7 avenue Jean Capelle, 69621 Villeurbanne, France. 2
Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, Ecole
Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France. 3
Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay,
route de Nozay, F-91460 Marcoussis, France. 4
Institut Lumière Matière (ILM), UMR5306 Université Lyon 1-CNRS Université de Lyon,
69622 Villeurbanne cedex, France
1
1. TEM Investigation of the InP nanowires InP NWs have been investigated by High-resolution transmission electron microscopy (HRTEM). Figure S1.a shows the dark field TEM image of a typical InP NW oriented along the wurtzite zone axis. In this orientation, wurtzite (Wz) and zinc-blende (ZB) crystal structures show two different diffraction patterns in which the spots belonging to one phase are well separated from those of the other. Therefore, a good contrast can be obtained between the two phases by selecting the spots of one of the two phases. A close view of the upper part of the NW is shown on Figure S1.b.
Figure S1: (a) Dark field TEM image of an InP NW. (b) Close view of the upper part of the NW. The NW has a perfect Wz crystallographic phase during the first 0.9-1 µm length. This length corresponds to the typical size of the InP NWs after the initial 10 mn axial growth at 380°C. Then, ZB insertions are observed in the upper part of the NW. This part is related to the axial
2
growth of the NW during the 20 mn growth at 340°C. This second step is required to increase the NW diameter which is usually in the 50-60 nm range after the first growth step. 2. Experimental setup The optical properties of the Wz InP NWs were investigated by photoluminescence (PL) measurements performed using a 50 mW 532 nm continuous wave (cw) diode-pumped solidstate laser as the excitation source and a nitrogen cooled silicon CCD detector coupled to a monochromator for the detection (Figure S2).
Figure S2: Experimental setup used for the PL study under hydrostatic pressure. Two high-pressure cycles have been made to probe the optical properties of Wz InP NWs with hydrostatic pressure. In the first measurement, ruby chips were added to the NWs to determine the pressure using the ruby fluorescence method. From these results, the pressure dependence of the A transition was extracted (Figure S3). The position of the A transition could not be determined for pressure higher than 3 GPa because of a weak signal to noise ratio (SNR), due to a decrease of the A peak intensity with pressure and due to a background emission related to the ruby chip. Then, a second high-pressure measurement was realized, but this time, without any ruby chip to improve the SNR (Figure 3.a of the paper). This
3
second pressure load was used to investigate the pressure dependence of the B transition and of the PL integrated intensity.
(a)
PL (arb. unit)
2.85 GPa
0 GPa 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70
Energy (eV)
Figure S3: High-pressure PL measurements with InP NWs and ruby chips.
3. Analysis of the experimental results As far as the elastic coefficients are concerned, we use the set calculated using LDA by C. Hajlaoui et al.1. These coefficients can also be estimated from the ZB ones using a model based on a rotation of the crystal structure and a correction due to the internal strain state. 2,3 The two sets can be found in Table S1.
4
Method
C11 (GPa)
C12 (GPa)
C13 (GPa)
C33 (GPa)
C44 (GPa)
C66 (GPa)
LDA
116.7
50.9
38.2
135.9
27.0
32.9
120.3
52.3
40.7
131.9
27.1
34.0
From ZB InP, using Ref 2 Table S1: Elastic coefficients (in GPa) of Wz InP. As far as the deformation potentials of Wz InP material are concerned, sets of parameters have been published in Ref 4 using three different ab initio calculation methods: HeydScuseria-Ernzerhof (HSE) density functional theory, generalized-gradient approximation in the Perdew-Burke-Ernzerhof (PBE) parameterization and single shot GW calculations. Another approach is to estimate the deformation potentials in Wz from the cubic approximation.5,6 All these sets of deformation potentials are reported in Table S2. Method
acz-D1 (eV)
act-D2 (eV)
D3 (eV)
D4 (eV)
PBE
-3.13
-7.20
5.55
-3.09
GW
-3.98
-7.43
5.67
-3.15
HSE
-4.05
-7.64
5.92
-3.28
0.37
-8.29
8.67
-4.33
From ZB InP using Ref 5 Table S2: Deformation potentials (in eV) of Wz InP. Two theoretical models are used to fit the experimental results. Figure S4 shows the fitting of the experimental results to extract the effective hydrostatic deformation potentials.
5
Energy (eV)
1.70 1.65 1.60 1.55 1.50 A Transition B Transition
1.45 1.40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Pressure (GPa) Figure 4: Fit of the experimental results using the Murnaghan equation of state and Equation 5 of the manuscript. References (1)
Hajlaoui, C. PhD Thesis, INSA Rennes, El Manar Tunis University, 2014.
(2)
Martin, R. M. Phys. Rev. B 1972, 6, 4546–4553.
(3)
Larsson, M. W.; Wagner, J. B.; Wallin, M.; Håkansson, P.; Fröberg, L. E.; Samuelson, L.; Wallenberg, L. R. Nanotechnology 2007, 18, 015504.
(4)
Hajlaoui, C.; Pedesseau, L.; Raouafi, F.; Cheikhlarbi, F. Ben; Even, J.; Jancu, J.-M. J. Phys. D. Appl. Phys. 2013, 46, 505106.
(5)
Sirenko, Y. M.; Jeon, J. B.; Lee, B. C.; Kim, K. W.; Littlejohn, M. A.; Stroscio, M. A.; Iafrate, G. J. Phys. Rev. B 1997, 55, 4360–4375.
(6)
6
Faria Junior, P. E.; Sipahi, G. M. J. Appl. Phys. 2012, 112, 103716.
Pressure dependent photoluminescence study of wurtzite InP nanowires N. Chauvin1, A. Mavel1,2, G. Patriarche3, B. Masenelli1, M. Gendry2, D. Machon4. 1
Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, INSA-
Lyon, 7 avenue Jean Capelle, 69621 Villeurbanne, France. 2
Université de Lyon, Institut des Nanotechnologies de Lyon (INL)-UMR5270-CNRS, Ecole
Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France. 3
Laboratoire de Photonique et de Nanostructures (LPN), CNRS, Université Paris-Saclay,
route de Nozay, F-91460 Marcoussis, France. 4
Institut Lumière Matière (ILM), UMR5306 Université Lyon 1-CNRS Université de Lyon,
69622 Villeurbanne cedex, France
1
1. TEM Investigation of the InP nanowires InP NWs have been investigated by High-resolution transmission electron microscopy (HRTEM). Figure S1.a shows the dark field TEM image of a typical InP NW oriented along the wurtzite zone axis. In this orientation, wurtzite (Wz) and zinc-blende (ZB) crystal structures show two different diffraction patterns in which the spots belonging to one phase are well separated from those of the other. Therefore, a good contrast can be obtained between the two phases by selecting the spots of one of the two phases. A close view of the upper part of the NW is shown on Figure S1.b.
Figure S1: (a) Dark field TEM image of an InP NW. (b) Close view of the upper part of the NW. The NW has a perfect Wz crystallographic phase during the first 0.9-1 µm length. This length corresponds to the typical size of the InP NWs after the initial 10 mn axial growth at 380°C. Then, ZB insertions are observed in the upper part of the NW. This part is related to the axial
2
growth of the NW during the 20 mn growth at 340°C. This second step is required to increase the NW diameter which is usually in the 50-60 nm range after the first growth step. 2. Experimental setup The optical properties of the Wz InP NWs were investigated by photoluminescence (PL) measurements performed using a 50 mW 532 nm continuous wave (cw) diode-pumped solidstate laser as the excitation source and a nitrogen cooled silicon CCD detector coupled to a monochromator for the detection (Figure S2).
Figure S2: Experimental setup used for the PL study under hydrostatic pressure. Two high-pressure cycles have been made to probe the optical properties of Wz InP NWs with hydrostatic pressure. In the first measurement, ruby chips were added to the NWs to determine the pressure using the ruby fluorescence method. From these results, the pressure dependence of the A transition was extracted (Figure S3). The position of the A transition could not be determined for pressure higher than 3 GPa because of a weak signal to noise ratio (SNR), due to a decrease of the A peak intensity with pressure and due to a background emission related to the ruby chip. Then, a second high-pressure measurement was realized, but this time, without any ruby chip to improve the SNR (Figure 3.a of the paper). This
3
second pressure load was used to investigate the pressure dependence of the B transition and of the PL integrated intensity.
(a)
PL (arb. unit)
2.85 GPa
0 GPa 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70
Energy (eV)
Figure S3: High-pressure PL measurements with InP NWs and ruby chips.
3. Analysis of the experimental results As far as the elastic coefficients are concerned, we use the set calculated using LDA by C. Hajlaoui et al.1. These coefficients can also be estimated from the ZB ones using a model based on a rotation of the crystal structure and a correction due to the internal strain state. 2,3 The two sets can be found in Table S1.
4
Method
C11 (GPa)
C12 (GPa)
C13 (GPa)
C33 (GPa)
C44 (GPa)
C66 (GPa)
LDA
116.7
50.9
38.2
135.9
27.0
32.9
120.3
52.3
40.7
131.9
27.1
34.0
From ZB InP, using Ref 2 Table S1: Elastic coefficients (in GPa) of Wz InP. As far as the deformation potentials of Wz InP material are concerned, sets of parameters have been published in Ref 4 using three different ab initio calculation methods: HeydScuseria-Ernzerhof (HSE) density functional theory, generalized-gradient approximation in the Perdew-Burke-Ernzerhof (PBE) parameterization and single shot GW calculations. Another approach is to estimate the deformation potentials in Wz from the cubic approximation.5,6 All these sets of deformation potentials are reported in Table S2. Method
acz-D1 (eV)
act-D2 (eV)
D3 (eV)
D4 (eV)
PBE
-3.13
-7.20
5.55
-3.09
GW
-3.98
-7.43
5.67
-3.15
HSE
-4.05
-7.64
5.92
-3.28
0.37
-8.29
8.67
-4.33
From ZB InP using Ref 5 Table S2: Deformation potentials (in eV) of Wz InP. Two theoretical models are used to fit the experimental results. Figure S4 shows the fitting of the experimental results to extract the effective hydrostatic deformation potentials.
5
Energy (eV)
1.70 1.65 1.60 1.55 1.50 A Transition B Transition
1.45 1.40
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Pressure (GPa) Figure 4: Fit of the experimental results using the Murnaghan equation of state and Equation 5 of the manuscript. References (1)
Hajlaoui, C. PhD Thesis, INSA Rennes, El Manar Tunis University, 2014.
(2)
Martin, R. M. Phys. Rev. B 1972, 6, 4546–4553.
(3)
Larsson, M. W.; Wagner, J. B.; Wallin, M.; Håkansson, P.; Fröberg, L. E.; Samuelson, L.; Wallenberg, L. R. Nanotechnology 2007, 18, 015504.
(4)
Hajlaoui, C.; Pedesseau, L.; Raouafi, F.; Cheikhlarbi, F. Ben; Even, J.; Jancu, J.-M. J. Phys. D. Appl. Phys. 2013, 46, 505106.
(5)
Sirenko, Y. M.; Jeon, J. B.; Lee, B. C.; Kim, K. W.; Littlejohn, M. A.; Stroscio, M. A.; Iafrate, G. J. Phys. Rev. B 1997, 55, 4360–4375.
(6)
6
Faria Junior, P. E.; Sipahi, G. M. J. Appl. Phys. 2012, 112, 103716.
