Direct band gap In Ga1−As/Ge type II strained quantum wells for short-wave infrared p–i–n photodetector

Abstract

a b s t r a c tWe theoretically investigate GaAs/Ge/InGaAs as a quantum wells for the design of short-wave infrared p-i-n photodetectors in which the quantum well Ge/InGaAs is the active region. At room temperature, strained Ge/In x Ga 1Àx As becomes a direct band gap when In composition x is lower than 2.5% and 5% respectively. We have calculated the electronic band parameters for the heterointerface Ge/In x Ga 1Àx As. Then, a type-II strain GaAs/Ge/In 0.35 Ga 0.65 As/GaAs quantum wells heterostructure optimized in terms of compositions and thicknesses is studied by solving Schrödinger equation as well as the absorption coefficient (>1.5 Â 10 4 cm À1 ). These computations have been used for the study of p-i-n infrared photodetectors operating at room temperature in the range 1.3-1.55 lm. The electron transport in the GaAs/Ge/In 0.35 Ga 0.65 As/GaAs multi-quantum wells-based p-i-n structure was analyzed and numerically simulated taking into account tunneling process and thermally activated transfer through the barriers mainly. The temperature dependence of dark current mechanisms and zero-bias resistance area product (R 0 A) have been analyzed. Extracted from current-voltage characteristics, R 0 A products above 3.6 Á 10 6 X cm 2 at 77 K were calculated, and the quantitative analysis of the J-V curves showed that the dark current density of Ge/In 0.35 Ga 0.65 As photodetector is dominated by generation-recombination processes. The suitability of the modeled photodetector is approved by its feasibility of achieving good device performance near room temperature operating at 1.55 lm. Quantum efficiency of $90% and responsivity $0.6 A/W, have been achieved.

Optical Gain and Radiative Current Density in Strain Compensated GaAsP/GaAsBi/GaAsP QWs Laser Structure

“…We previously reported growth studies which confirm the incorporation of Bi and P in the wells and barriers respectively [23]. The purpose of the present work is to exhibit the effects instigated by the bismide states, taking into account the influence of the modified band offset parameters (Table 1) [24,25] on band structures and optical gain spectra for a strained GaAsP/GaAsBi/GaAsP QWs. This latter effect is supported by the fact that the modified offset parameters [26] play a fundamental role in energy dispersion, and thus in optical gain.…”

“…Moreover, it was computed using the refractive indices n op extracted from Table 1, following the procedure assumed in Ref. [24]. The carried out calcu-lations at 300K indicated that the incorporation of bismide reduces the radiative efficiency of the structure (Figure 8a).…”

Flexible Photodetectors Based on 1D Inorganic Nanostructures

“…Compared with the other types of PDs, infrared PDs have great importance in numerous civilian and military applications, including heat capacity mapping, thermal remote sensing, target tracking and environment monitoring . Common materials for infrared PDs include GaSb, GaAs, InAs, and HgCdTe . Recent years, 1D nanostructures are also used in infrared PDs.…”