The Dependence of InAs/InAsSb Superlattice Detectors’ Spectral Response on Molecular Beam Epitaxy Growth Temperature

Abstract

In this paper, we report on the influence of molecular beam epitaxial (MBE) growth temperature on the spectral response of the long-wavelength infrared radiation (LWIR), three-stage thermoelectrically (TE) cooled (T = 210, 230 K) InAs/InAsSb type-II superlattice (T2SL)-based detectors grown on the GaSb/GaAs buffer layers/substrates. Likewise, antimony (Sb) composition and the superlattice (SL) period could be used for spectral response selection. The presented results indicate that the growth temperature affects the 50% cut-off (λ50%cut-off) of the fabricated devices and could be used for operating wavelength tunning. Assuming constant Sb composition and T2SL period during MBE process, the growth temperature is presented to influence λ50%cut-off covering entire LWIR (e.g., temperature growth change within the range of 400–450 °C contributes to the λ50%cut-off ~ 11.6–8.3 μm estimated for operating temperature, T = 230 K). An increase in temperature growth makes a blueshift of the λ50%cut-off, and this is postulated to be a consequence of a modification of the SL interfaces. These results show an approach to the T2SL InAs/InAsSb deposition optimization by the growth temperature in terms of the spectral response, without influencing the T2SLs’ structural properties (Sb composition, SL period).

Keywords

• IR detector
• type-II superlattices
• InAs/InAsSb
• LWIR
• MBE
• spectral response