High-responsivity GeSn short-wave infrared p-i-n photodetectors

Abstract

Surface-illuminated GeSn p-i-n photodetectors (PDs) with Ge0.964Sn0.036 active layer on Ge substrate were fabricated. Photodetection up to 1.95 μm is achieved with a responsivity of 0.13 A/W. High responsivities of 0.56 and 0.71 A/W were achieved under a reverse bias voltage of 3 V at 1640 and 1790 nm, respectively. A low dark current of 1.08 μA was obtained at a reverse bias of 1 V with a diameter of 150 μm, which corresponds to a current density of 6.1 mA/cm2. This value is among the lowest dark current densities reported among GeSn PDs.

Dislocation density and strain-relaxation in Ge 1−x Sn x layers grown on Ge/Si (0 0 1) by low-temperature molecular beam epitaxy

“…Moreover, Ge1-xSnx has been demonstrated to undergo an indirect to direct band gap transition for Sn-content of ~ 7 % and above (when fully relaxed) [2,3]. Intensive research efforts over the last five years have thus led to the fabrication of Ge1-xSnx based photoconductors [4,5], photodiodes [6,7,8], and light emitting diodes [3,9], and also to the first demonstration of optically pumped lasing in 2015 [10]. The spectral response of Ge1-xSnx based photodetectors now extends all the way up to 2.4 m [11].…”

Band engineering and absorption spectra in compressively strained Ge0.92Sn0.08/Ge (001) double quantum well for infrared photodetection

“…Recently, Alexander et al [17] studied the band gap character of compressively strained GeSn/Ge(001) quantum wells (QWs) grown by MBE and they demonstrated that these pseudomorphic layers could serve as active regions in light emitting devices in Ge-photonic circuits based on germanium-oninsulator substrates. GeSn p-i-n photodetectors with Sn contents up to 3.6% in active layer have been recently fabricated on Ge substrate with a cut-off detection wavelength reaching 1.95 µm [18]. The design and modelling of quantum heterostructures such as coupled multiple quantum wells, superlattices or nanowire arrays for photodetectors based on strained SiGeSn is therefore of particular interest in view of their integration on silicon using SiGe-CMOS compatible technology.…”

Optical Characterization of Si-Based Ge1−x Sn x Alloys with Sn Compositions up to 12%

“…1 Among the various material systems that could be integrated on Si, the Ge 1Àx Sn x alloy has attracted much attention recently due to the following reasons: (1) Capability of monolithic integration on Si; 2 (2) Availability of direct bandgap material; 3 and (3) tunable bandgap covering broad shortwave-and mid-infrared (IR) wavelength range. 4 During the last decade, the GeSn-based optically pumped laser, 5 light emitting diode, [6][7][8][9][10][11][12] photo detector [13][14][15][16][17][18][19][20] have been demonstrated, and the GeSn modulator has been investigated 21,22 which make up a complete set of components for Si photonics. For these prototype devices, the material characteristics have turned out to be the decisive factor for the performance of the device.…”