Further information on MOVPE growth of SLS materials can be found, for example, in the works of Zhang et al. However, most of the studies presented so far have been focused on solid-source MBE, which offers lower growth rates, lower growth temperatures, and an easier handling of Sb-based materials. Modern epitaxy techniques such as metal-organic vapor-phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) permit the crystalline growth of very good quality SLS.

Moreover, in such a stack of very thin layers, interfaces play a significant role on the material quality and optoelectrical properties, which implies a thickness and composition control of the order of the atomic monolayer thickness. Hence, the control of each layer is very critical. Krishna, in Comprehensive Semiconductor Science and Technology, 2011 6.06.3.3.1 Material uniformityĭepending on the desired cutoff wavelength, each layer of InAs/Ga(In)Sb of the SLS period ranges from 5 to 20 atomic monolayers (MLs) (about 15–60 Å). The activation energies derived from Arrhenius plots of dark current, 170, 204, and 226 meV for bias voltages + 9, −9, and 0.1 V respectively, agree with the cut-off wavelengths observed in the photoresponse curve. This QWIP remains background limited up to a detector temperature of 100 K for biases between −7.5 V and +2.5 V. Compared with the GaAs/GaInP QWIP reported in the last section, the peak wavelength increased slightly. The photoresponse has a peak around 4 μm with broad maxima. Such asymmetry could be related to either a structural difference in the two quantum well interfaces or to dopant migration during the material growth. This arises from an asymmetric quantum well potential profile. 72 The effect of the quaternary alloy was to reduce the valence band offset relative to lattice matched GaAs and thus increase the cut-off wavelength.Ī photovoltaic effect is observed from the photoresponse curve (see Figure 1 in reference 72). In 0.29As 0.39P 0.61 QWIP was grown by LP-MOCVD with 50 periods of 30 Å wide GaAs quantum wells separated by 280 Å wide GaInAsP (Eg = 1.8 eV at T=300 K) barriers. To increase the cut-off wavelength, a lattice-matched GaAs/Ga 0.71. Razeghi, in Handbook of Infra-red Detection Technologies, 2002 p-type GaAs/GaInAsP QWIP

Cable cut off wavelength