Interband cascade infrared photodetectors based on Ga-free InAs/InAsSb superlattice absorbers

Abstract

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.

Self‐Healing of Proton‐Irradiated Organic Photodiodes and Photovoltaics

“…Another critical parameter is the detectivity, which indicates the sensitivity of the PD to weak optical signals. The detectivity limited by Johnson noise D th * , which stands for the maximum possible detectivity of a self‐powered PD, can be determined by the following equation: [ 57–59 ] $$$$\begin{equation}\ D_{th}^* = \frac{{{\mathrm{R}}\sqrt {\mathrm{A}} }}{{{i}_{{\mathrm{thermal}}}}}\ \end{equation}$$$$where A is the active area of the device and $${i}_{{\mathrm{thermal}}} = \sqrt {\frac{{4{k}_BT}}{{{R}_{sh}}}} \ $$. Here k B is Boltzmann constant, Т is absolute temperature, and R sh is shunt resistance, which was determined from the dark differential resistance at zero bias (see Figure S7 and Table S1, Supporting Information).…”

“…Another critical parameter is the detectivity, which indicates the sensitivity of the PD to weak optical signals. The detectivity limited by Johnson noise D th *, which stands for the maximum possible detectivity of a self-powered PD, can be determined by the following equation: [57][58][59]…”

Signal, noises, and detectivities in multi-stage infrared photodetectors

“…Also, monolithically integrated mid-IR ICL and ICIP with a record-high detectivity (~2×10 10 Jones) was demonstrated operating at room temperature [30], paving the way for important applications such as on-chip miniaturized sensors, spectrometers, optical communication and processing. Recently, preliminary ICIPs with Ga-free InAs/InAsSb SL absorbers were reported to explore the longer carrier lifetime [44][45].…”

Response Time of III-V Multistage Detectors Based on the “Ga-Free” InAs/InAsSb Type-II Superlattice

“…There are many papers confirming the possibility of using ICIPs structures based on the III-V materials family, where Yang et al developed a pioneering theory and presented ICIPs operating within SWIR, MWIR, and LWIR ranges based on both T2SLs InAs/GaSb and InAs/InAsSb [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. As mentioned earlier, the use of a cascade structure makes it possible to improve the detector's detectivity by the increase in QE (and when biased by shot noise suppression by the number of stages, where the optimal number of stages depends on the absorption coefficient and thickness of the single absorber N s = 1/2αd) and to decrease the response time of such devices by a significant reduction in the single absorber thickness (reduced carrier diffusion time) [18][19][20].…”