%0 Journal Article %1 2022SeScT..37e5009O %A Oehme, Michael %A Kasper, Erich %A Weißhaupt, David %A Sigle, Eric %A Hersperger, Tim %A Wanitzek, Maurice %A Schwarz, Daniel %D 2022 %J Semiconductor Science Technology %K iht journal %N 5 %P 055009 %R 10.1088/1361-6641/ac61fe %T Two-dimensional hole gases in SiGeSn alloys %V 37 %X Two-dimensional hole gases are demonstrated in modulation doped SixGe1−x−ySny quantum wells (QWs), which are embedded in Si0.2Ge0.8 barrier layers. The modulation doped QW structures are fabricated with molecular beam epitaxy on a thin (100 nm) virtual SiGe substrate on a (001) oriented Si substrate. The virtual substrate (VS) concept utilizes the Si diffusion into an as- grown thin, strain relaxed Ge layer during a following annealing step. The lateral lattice spacing of the SiGe-VS could be varied by the annealing temperature in the range between 830 ◦C and 860 ◦C. Half-hour anneal at 848 ◦C results in nearly strain free growth for the following Si0.2Ge0.8 barrier layer. Boron doping above an undoped 10 nm spacer on top of the 15 nm QW provides a reservoir for hole transfer from the barrier to the well. Electrical conductivity, sheet hole density ps and mobility are measured as function of temperature. In all investigated SixGe1−x−ySny channels the Hall measurements show the typical freeze out of holes outside the QW. Alloy scattering dominates the low-temperature mobility by adding Sn or Si to the Ge reference well. A linear relationship for the charge transfer from the modulation doping into the undoped SixGe1−x−ySny channel as function of the lattice mismatch between the channel material and the matrix material could be found at low-temperatures (8 K). An analytical model for this charge transfer confirms the nearly linear relationship by considering the triangular shape of the potential in modulation doped QW structures.

@article{2022SeScT..37e5009O, abstract = {Two-dimensional hole gases are demonstrated in modulation doped SixGe1−x−ySny quantum wells (QWs), which are embedded in Si0.2Ge0.8 barrier layers. The modulation doped QW structures are fabricated with molecular beam epitaxy on a thin (100 nm) virtual SiGe substrate on a (001) oriented Si substrate. The virtual substrate (VS) concept utilizes the Si diffusion into an as- grown thin, strain relaxed Ge layer during a following annealing step. The lateral lattice spacing of the SiGe-VS could be varied by the annealing temperature in the range between 830 ◦C and 860 ◦C. Half-hour anneal at 848 ◦C results in nearly strain free growth for the following Si0.2Ge0.8 barrier layer. Boron doping above an undoped 10 nm spacer on top of the 15 nm QW provides a reservoir for hole transfer from the barrier to the well. Electrical conductivity, sheet hole density ps and mobility are measured as function of temperature. In all investigated SixGe1−x−ySny channels the Hall measurements show the typical freeze out of holes outside the QW. Alloy scattering dominates the low-temperature mobility by adding Sn or Si to the Ge reference well. A linear relationship for the charge transfer from the modulation doping into the undoped SixGe1−x−ySny channel as function of the lattice mismatch between the channel material and the matrix material could be found at low-temperatures (8 K). An analytical model for this charge transfer confirms the nearly linear relationship by considering the triangular shape of the potential in modulation doped QW structures.}, added-at = {2022-05-25T10:09:08.000+0200}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2022SeScT..37e5009O}, author = {Oehme, Michael and Kasper, Erich and Weißhaupt, David and Sigle, Eric and Hersperger, Tim and Wanitzek, Maurice and Schwarz, Daniel}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/29eb0a00722d6620192bad82cb95dab44/ihtpublikation}, description = {Two-dimensional hole gases in SiGeSn alloys - NASA/ADS}, doi = {10.1088/1361-6641/ac61fe}, eid = {055009}, interhash = {52a35d4dc02a5a9a2ea1bf4d4e6e8103}, intrahash = {9eb0a00722d6620192bad82cb95dab44}, journal = {Semiconductor Science Technology}, keywords = {iht journal}, month = may, number = 5, pages = 055009, timestamp = {2022-05-25T08:09:08.000+0200}, title = {Two-dimensional hole gases in SiGeSn alloys}, volume = 37, year = 2022 }