Time resolved photoluminescence spectroscopy of narrow gap Hg1−xCdxTe/CdyHg1−yTe quantum well heterostructures

Abstract

Photoluminescence (PL) spectra and kinetics of narrow gap Hg1−xCdxTe/CdyHg1−yTe quantum well (QW) heterostructures grown by molecular beam epitaxy technique are studied. Interband PL spectra are observed from 18 K up to the room temperature. Time resolved studies reveal an additional PL line with slow kinetics (7 μs at 18 K) related to deep defect states in barrier layers. These states act as traps counteracting carrier injection into QWs. The decay time of PL signal from QW layers is about 5 μs showing that gain can be achieved at wavelengths 10–20 μm by placing such QWs in HgCdTe structures with waveguides.

Investigation of possibility of VLWIR lasing in HgCdTe based heterostructures

“…Unlike bulk material the energy spectrum of QW structures is characterized by close effective masses of electrons and holes that should result in mitigation of the Auger recombination. This is indirectly confirmed by low temperature quenching of PL in QW structures as compared to bulk samples [13]. PL signal at room temperature is easily detected not only in wide QW but also in rather narrow wells ( figure 2(a)).…”

Long wavelength superluminescence from narrow gap HgCdTe epilayer at 100 K

“…At the same time, in QW structures, the decay time of interband PL at 13 lm reaches 5 ls (Ref. 18), which means that the carrier density necessary for light amplification can be achieved under reasonable pumping intensity. Recent studies also demonstrate that temperature quenching of PL in QW is weaker as compared to bulk structures and PL signal can be observed even at room temperature.…”

“…Recent studies also demonstrate that temperature quenching of PL in QW is weaker as compared to bulk structures and PL signal can be observed even at room temperature. 18,19 Thus, one can expect that emission frequency in HgCdTe based lasers could be varied in a wide spectral range by changing the operating temperature while wavelength tuning in QCL is rather limited. 20 The above mentioned points suggest that HgCdTe material is promising for long wavelength lasers.…”

THz lasers based on narrow-gap semiconductors

“…Our recent studies provide some evidence of Auger mitigation in HgCdTe QWs as well. The temperature quenching of photoluminescence in HgCdTe QWs with bandgap energy ~ 60 -100 meV is weaker than in bulk samples with the same bandgap energy [11,12].…”