AlInAsSb/GaSb staircase avalanche photodiode

Abstract

Over 30 years ago, Capasso and co-workers [IEEE Trans. Electron Devices 30, 381 (1982)] proposed the staircase avalanche photodetector (APD) as a solid-state analog of the photomultiplier tube. In this structure, electron multiplication occurs deterministically at steps in the conduction band profile, which function as the dynodes of a photomultiplier tube, leading to low excess multiplication noise. Unlike traditional APDs, the origin of staircase gain is band engineering rather than large applied electric fields. Unfortunately, the materials available at the time, principally Al x Ga 1Àx As/GaAs, did not offer sufficiently large conduction band offsets and energy separations between the direct and indirect valleys to realize the full potential of the staircase gain mechanism. Here, we report a true staircase APD operation using alloys of a rather underexplored material, Al x In 1Àx As y Sb 1Ày , lattice-matched to GaSb. Single step "staircase" devices exhibited a constant gain of $2Â, over a broad range of applied bias, operating temperature, and excitation wavelengths/intensities, consistent with Monte Carlo calculations. V

Enhanced Carrier Multiplication in InAs Quantum Dots for Bulk Avalanche Photodetector Applications

“…Taking advantage of the discrete energy levels and the associated phonon bottleneck effect of QDs, the kinetic energy relaxation of hot carriers via electron–phonon scattering is expected to be suppressed in QD multiplication structures and consequently enhanced multiplication performances are predicted. Moreover, carriers will gain extra kinetic energy when drifting from a wider band gap matrix barrier into a narrower band gap QD layer due to band discontinuities, which is similar to that in staircase APDs, further enhancing the impact ionization rate. In particular, localization of carrier impact ionization events in QDs may lead to a more deterministic multiplication factor and consequently reduced excess noise.…”

“…The reported maximum M were less than 10 and responsivities were no higher than 5 A W −1 , while information on the k eff were not included. The one‐stage Al 0.7 In 0.3 As 0.31 Sb 0.69 PIN staircase APD revealed an M of 4 at 300 K and a corresponding responsivity of 1 A W −1 , which is promising as an early stage demonstration. The InGaAsP/InAlAs SL multiplication structure in an InGaAs SAM APD had shown a slightly enhanced maximum M of 50 compared to the InAlAs bulk multiplier, which has been presumably related to the conduction band discontinuity at the SL interfaces.…”

“…In Table 1 , we have summarized the APD architectures as well as the measured primary performance parameters for both our QD device and other state‐of‐the‐art APDs incorporated with QDs or enhanced multiplier structures (staircase, SLs, and impact ionization engineering (IIE)). The multilayer stacked InAs QDs in the PIN or SAM APDs in refs.…”

Toward deterministic construction of low noise avalanche photodetector materials

“…First, digital alloys could be viewed as simply a highly scaled version of the MQW APDs where the impact ionization threshold is modulated with the composition. 21,22 This is similar to Capasso's staircase APD 49,50 in which an electron can gain a large amount of energy when moving from a large bandgap material to a small bandgap material, allowing for deterministic impact ionization. This view would suggest that key parameters would be (1) a large conduction band offset, relative to the bandgap, to enhance electron-related impact ionization and potentially (2) an indirect-direct bandgap transition between the constituent materials to enhance scattering and initiate impact ionization.…”

Al_xIn_1-xAs_ySb_1-y photodiodes with low avalanche breakdown temperature dependence

“…Previously reported Al x In 1-x As y Sb 1-y PIN and SACM APDs, which are lattice matched to GaSb, have demonstrated low excess noise, k = 0.01~0.05, and high absorption efficiency covering a wide optical spectrum [6][7][8][9]. In this paper we report temperature-dependent studies of these Al x In 1-x As y Sb 1-y APDs.…”