Optical deformation potentials for PbSe and PbTe

Abstract

The values of optical deformation potentials (D u and D d ) for PbSe and PbTe are analyzed using absorption, luminescence and x-ray diffraction data on high quality, deep quantum well PbSe/ PbSrSe and PbTe/ PbEuTe structures. Published optical data on PbTe/ BaF 2 structures were also used. It is important for these evaluations to use the value of isotropic deformation potential ͑D iso ͒ which is determined from the low temperature hydrostatic pressure experiments and the intervalley splitting which was determined from differential absorption spectroscopy. The fitting procedure was done using an accurate k · p model for the band structure near the fundamental gap including anisotropy, multivalley, and band nonparabolicity effects. Photoluminescence was measured in pulsed mode at 4 and 77 K, which gives the lowest energy state in the rectangular well. The strain and well parameters were measured with a high resolution x-ray diffractometer. We find the new optical deformation potential values at low temperatures: D u = −0.2 and −0.5 eV, and D d = 5.3 and 3.5 eV for PbSe and PbTe, respectively.

Optical and structural properties of Pb1−xEuxTe/CdTe//GaAs (001) heterostructures grown by MBE

“…The PL energies observed in our PbTe/ CdTe and PbEuTe/CdTe MQWs are substantially (about 150 meV) higher than that expected for PbTe at liquid helium temperatures (E g ¼190 meV). This experimental finding agrees with previous photoluminescence reports on PbTe/CdTe multilayers [7,10,11,19,24]. This large difference can be attributed to the quantum size effect and to the increase in the PbEuTe bandgap due to strain originating from huge difference between thermal expansion coefficients, as discussed above.…”

Multivalley transport and the integer quantum Hall effect in a PbTe quantum well

“…Note that in the following, we neglect the valley splitting due to strain, as a reasonable estimate for this splitting is ␦E g ᐉ − ␦E g o Ϸ 1.5 meV, which is significantly smaller than the confinement energy scale and is therefore unable to change the order of subbands in the quantum well. 18 In the presence of a magnetic field, each of these subbands splits into spin-resolved Landau levels, whose following expressions are derived from the exact solutions of the 3D case when B ជ ʈ ͓111͔: 1…”

Weak electron–phonon coupling contributing to high thermoelectric performance in n-type PbSe

“…By definition, D iso is calculated by subtracting the isotropic deformation (40) determined D iso ¼ 14 eV at 295 K for PbSe in quantum well structures from photoluminescence and X-ray diffraction data. Ferreira (41) calculated D iso to be approximately 10 eV for PbTe using the Augmented-PlaneWave method.…”