Plasmon-enhanced mid-infrared luminescence from polar and lattice-structure-mismatched CdTe/PbTe single heterojunctions

Abstract

We propose by exploring CdTe/PbTe single heterojunctions (SHs) that the abnormal enhancement of mid-infrared light emission from CdTe/PbTe heterostructures is due to coupling with surface plasmons. It is discovered that the observed intense mid-infrared luminescence in the SHs comes from the inherent polar interface character and coupling of surface plasmons localized at the metallic CdTe/PbTe interface to light emitted from the narrow gap PbTe. The finding offers an approach to manipulate mid-infrared light and to fabricate improved mid-infrared optoelectronic devices.

Molecular beam epitaxy and characterizations of PbTe grown on GaAs(211) substrates using CdTe/ZnTe buffers

“…4(b) shows a mid-infrared PL spectrum of the PbTe/CdTe/ZnTe/ GaAs(211) sample measured at room temperature. The peak of PL locates at about 3.5 μm in wavelength (0.35 eV in photon energy) which is slightly larger than the band gap of PbTe (0.32 eV) at room temperature but is in agreement with the PL results of PbTe grown on the BaF 2 (111) substrate [13]. The blue shift of the PL peak can be ascribed to the broadening of the bandgap of PbTe due to the heating effect caused by laser excitation because the PbTe band gap has a positive coefficient versus temperature.…”

“…Table 2 lists electron mobilities and carrier concentrations of the samples grown at different temperature for PbTe. The room temperature electron mobilities measured here are close to the hole mobility of PbTe grown on BaF 2 (111) substrates [13], which is expected as PbTe has a symmetric band structure for electron and holes. The sample grown at 250 1C has the highest electron mobility within the four samples, verifying again that 250 1C is the most suitable substrate temperature for the growth of PbTe films.…”

“…The PbTe/CdTe/ZnTe/GaAs(211) samples grown at different temperatures were employed to characterize the electrical properties. The results of both low-temperature and room-temperature Hall effect measurements show that PbTe is a n-type semiconductor with electron concentrations of $ 5 Â 10 17 cm À 3 , which is different from p-type PbTe grown on BaF 2 (111) [13,20]. The CdTe buffer layers are semi-insulating.…”

“…Koike et al grew a CdTe buffer on GaAs(100) substrates using molecular beam epitaxy (MBE), then grew a PbTe film on the CdTe buffer [12]. PbTe/CdTe quantum wells and PbTe quantum dots embedded in CdTe matrices were realized [13,14]. In comparison with the epitaxy of PbTe on Si using BaF 2 /CaF 2 buffer layers, the utilization of GaAs substrates and CdTe buffers make it much easier to fabricate devices and manufacture readout ICs.…”

Quantum Oscillations in a Two-Dimensional Electron Gas at the Rocksalt/Zincblende Interface of PbTe/CdTe (111) Heterostructures

“…An effective mass of m* ∼ 0.09 m e is obtained from the fitting at all magnetic fields. The electron effective mass of the Γ valley in CdTe is m Γ ∼ 0.11 m e , 21 whereas the in-plane effective mass of the L valley in PbTe is rather small, m in-plane ∼ 0.024m e . 29 The derived effective mass seems to suggest that the 2DEG extends into both materials.…”