Vertical carrier transport in strain-balanced InAs/InAsSb type-II superlattice material

Abstract

Anisotropic carrier transport properties of unintentionally doped InAs/InAs0.65Sb0.35 type-II strain-balanced superlattice material are evaluated using temperature- and field-dependent magnetotransport measurements performed in the vertical direction on a substrate-removed metal-semiconductor-metal device structure. To best isolate the measured transport to the superlattice, device fabrication entails flip-chip bonding and backside device processing to remove the substrate material and deposit contact metal directly to the bottom of an etched mesa. High-resolution mobility spectrum analysis is used to calculate the conductance contribution and corrected mixed vertical-lateral mobility of the two carrier species present. Combining the latter with lateral mobility results from in-plane magnetotransport measurements on identical superlattice material allows for the calculation of the true vertical majority electron and minority hole mobilities; amplitudes of 4.7 ×103 cm2/V s and 1.60 cm2/V s are determined at 77 K, respectively. The temperature-dependent results show that vertical hole mobility rapidly decreases with decreasing temperature due to trap-induced localization and then hopping transport, whereas vertical electron mobility appears phonon scattering-limited at high temperature, giving way to interface roughness scattering at low temperatures, analogous to the lateral electron mobility but with a lower overall magnitude.

Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

“…Since smaller-area diodes are more dependent on surface effect (i.e., lateral diffusion current), D could be estimated in the limit r ⟶ 0 as = . Thus, we estimate an additional area As = 1.46 × 10 −5 cm² from the intersection of the fitted line with the x-axis, then a lateral diffusion length of 21.5 µm is deduced at 150 K, comparable to hole diffusion length values reported in MWIR devices [20][21][22] at this temperature. Hence, due to the additional surface area created by the important lateral diffusion length, a correction in the photodetector area is necessary to obtain the real electric performance.…”

“…An increase in the QE with the temperature, from 47% at 90 K to 62% at 220 K, is observed. This QE increment with temperature is due to the increase mobility of minority carriers and therefore in vertical diffusion length at temperatures higher than 90 K [6,21,25].…”

Structural, Optical and Electrical Characterizations of Midwave Infrared Ga-Free Type-II InAs/InAsSb Superlattice Barrier Photodetector

“…However, because heavy holes are mainly confined in the InAsSb layer, vertical transport will have to be investigated. Very recent results show that heavy hole mobility is strongly temperature dependant [31,32].…”

“…However, because heavy holes are mainly confined in the InAsSb layer, vertical transport will have to be investigated. Very recent results show that heavy hole mobility is strongly temperature dependant [31,32]. The Table 1 summarizes the structural and optical baseline values routinely used as a quality indicator to evaluate the performance of Ga-free InAs/InAsSb T2SL structures.…”

Electro-optical characterizations to study minority carrier transport in Ga-free InAs/InAsSb T2SL XBn midwave infrared photodetector

“…Different studies have been realized so far using different theoretical and experimental techniques. [8][9][10] In this paper, we report the extraction of different transport parameters of an InAs/InAsSb T2SL XBn detector. The XBn device design consists of a unipolar conduction band barrier layer (BL) inserted between n-type absorber and contact layers (AL and CL respectively).…”