Electroreflectance spectroscopy of strained Si1−xGex layers on silicon

Single phase Si1−xGex nanocrystals and the shifting of the E1 direct energy transition

“…We recall here that the lowest direct transition point of Si can be found only much higher, at E Γ1 =3.4 eV. Upon consideration of Ge energy band structure, we see that direct energy transition at ≈2 eV was identified for E 1 near the midpoint between Γ and L [2,3,30,31]. Three other direct transitions below 5.0 eV are also indicated: E 0 ≈0.8 eV and E 3.5 eV 0 » ¢ correspond to direct transitions at Γ point (k=0).…”

“…Mixing Si and Ge together into SiGe alloys attracts much attention due to the compelling optoelectronics properties of these materials. One of the most interesting points is the possibility to tailor the electronic band structures of the alloys between those of bulk Si and Ge [1][2][3]. Important technological breakthroughs and applications in solid-state electronic devices resulted in the development of exceptionally high speed transistors [4], heterojunction long-wavelength infrared detectors [5] that could replace Er-based technology [6], lithium-ion battery anodes [7][8][9], Si-Ge p-i-n solar cells [10], and Si-Ge nanodot superlattices for thermal transport [11].…”

Quantum-Confined Stark Effect in Ge/SiGe Quantum Wells on Si for Optical Modulators

“…The lowest conduction band at the zone center in Ge is a Γ 2 band [22], and hence we consider the Γ 2 band in Si [35] for calculating the conduction band offset. This Γ 2 band in Si is at an energy of ∼4.175 eV above the top of the valence bands in pure Si.…”