Numerical study on the optical and carrier recombination processes in GeSn alloy for E-SWIR and MWIR optoelectronic applications

Abstract

The Ge_1-xSn_x alloy is a promising material for optoelectronic applications. It offers a tunable wavelength in the infrared (IR) spectrum and high compatibility with complementary metal-oxide-semiconductor (CMOS) technology. However, difficulties in growing device quality Ge_1-xSn_x films has left the potentiality of this material unexplored. Recent advances in technological processes have renewed the interest toward this material paving the way to potential applications. In this work, we perform a numerical investigation on absorption coefficient, radiative recombination rate, and Auger recombination properties of intrinsic and doped Ge_1-xSn_x for application in the extended-short wavelength infrared and medium wavelength infrared spectrum ranges. We apply a Green's function based model to the Ge_1-xSn_x full electronic band structure determined through an empirical pseudopotential method and determine the dominant recombination mechanism between radiative and Auger processes over a wide range of injection levels.

Direct bandgap type-I GeSn/GeSn quantum well on a GeSn- and Ge- buffered Si substrate

“…To address this issue, the compensated Sn incorporation approach, i.e., adjusting the SnCl 4 flow to compensate the reduced Sn incorporation efficiency, was used to achieve the symmetrical QW structure. Figure 4 4 flow, the Sn depletion after well region can be minimized. The change in carrier distribution and QW optical characteristics due to this slight variation of Sn composition thereupon can be neglected.…”

“…[1][2][3][4][5][6][7][8][9] The successful demonstration of direct bandgap GeSn light emitting diodes (LEDs), and optically-pumped GeSn lasers, [10][11][12][13][14] indicates the great potential of GeSn for Si-based light sources. GeSn LEDs with double heterostructures (DHS) 11,[15][16][17][18][19][20][21][22] and quantum wells (QWs) [23][24][25][26][27][28][29][30][31] have been reported.…”

High-Bandwidth Extended-SWIR GeSn Photodetectors on Silicon Achieving Ultrafast Broadband Spectroscopic Response

“…The main reason underlying the higher D * of InGaAs comes from its low dark current density as shown in Figure (c). This is not surprising, as this technology has been benefiting from decades-long research on material and device optimization . For GeSn, the current density at 78 K shows a significant increase as the reverse bias increases, indicating an electric-field-enhanced trap-assisted thermionic emission owing to the induced band bending, which depicts a Poole–Frenkel leakage effect. , It is noted that there are more than 2 orders of magnitude reduction in dark current density at −0.15 V at 78 K relative to that at 293 K. This could be explained by the significant reduction in the Poole–Frenkel effect at a bias close to the built-in junction potential and the negligible phonon-assisted trap leakage.…”

High-Bandwidth Extended-SWIR GeSn Photodetectors on Silicon Achieving Ultrafast Broadband Spectroscopic Response

“…This is not surprising as this technology has been benefiting from decades-long research on material and device optimization. 33 For GeSn, the current density at 78 K shows a significant increase as the reverse bias increases indicating an electric-field enhanced trap-assisted thermionic emission owing to the induced band bending which depicts a Poole-Frenkel leakage effect. 32,34 It is noted that there are more than two orders of magnitude reduction in dark current density at − 0.15 V at 78 K relative to that at 293 K. This could be explained by the significant reduction in the Poole-Frenkel effect at a bias close to the built-in junction potential and the negligible phonon-assisted trap leakage.…”