We present resonant tunneling diode-photodetectors (RTD-PDs) with GaAs0.15Sb0.85/AlAs0.1Sb0.9 double barrier structures combined with an additional quaternary Ga0.64In0.36As0.

We present an interband cascade infrared photodetector based on Ga-free type-II superlattice absorbers. Substituting the more standard InAs/GaSb superlattice for a Ga-free superlattice with InAs/InAsSb requires an inverted carrier extraction path. A hole-ladder in the electron-barrier, instead of an electron-ladder in the hole-barrier, is employed to achieve photovoltaic operation. At elevated temperatures, seven negative-differential-conductance (NDC) regions are observed that arise from electrons tunneling through the electron barriers of the seven cascade stages. The detector operates in the photovoltaic mode at room temperature with a cutoff wavelength of 8.5  μm. At the NDC regions, the device features responsivity peaks under laser illumination reaching 0.45 A/W at room temperature at [Formula: see text] = 5.27  μm. This exceeds its highest measured low-temperature value of 0.22 A/W at this wavelength by a factor of 2.

We have studied the optical and electronic transport properties of n-type AlSb/GaInAsSb double barrier quantum well resonant tunneling diodes (RTDs). The RTDs were grown by molecular beam epitaxy on GaSb substrates. Collector, quantum well, and emitter regions are comprised of the lattice-matched quaternary semiconductor Ga0.64In0.36As0.33Sb0.67. Photoluminescence emission spectra reveal a direct bandgap semiconductor with a bandgap energy of Eg≈0.37 eV, which corresponds to a cut-off wavelength of λ≈3.3 μm. The composition-dependent bandgap energy is found to follow Shim’s model. At room temperature, we observe resonance current densities of jres=0.143 kA cm−2 with peak-to-valley current ratios of up to PVCR=6.2. At cryogenic temperatures T<50 K, the peak-to-valley current ratio increases up to PVCR=16.

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