Formation of carbon-induced germanium dots

A very small amount of pre-deposited C on a Si substrate causes island formation after epitaxial growth of less than 2 monolayers Ge. These C-induced Ge dots can be as small as 10 nm in lateral size and 1 nm in height. Their areal density is 1011 cm−2. Intense photoluminescence signal from these small Ge quantum dots is observed reaching a maximum for 2.1±0.3 monolayers of Ge. In the initial stages of island formation, the optical transition of the wetting layer is blue-shifted by strain compensation effects. We propose spatially indirect mechanisms of radiative recombination between electrons confined in the underlying wetting layer and holes confined in the Ge islands.A very small amount of pre-deposited C on a Si substrate causes island formation after epitaxial growth of less than 2 monolayers Ge. These C-induced Ge dots can be as small as 10 nm in lateral size and 1 nm in height. Their areal density is 1011 cm−2. Intense photoluminescence signal from these small Ge quantum dots is observed reaching a maximum for 2.1±0.3 monolayers of Ge. In the initial stages of island formation, the optical transition of the wetting layer is blue-shifted by strain compensation effects. We propose spatially indirect mechanisms of radiative recombination between electrons confined in the underlying wetting layer and holes confined in the Ge islands.

[1]  G. Capellini,et al.  Atomic Force Microscopy and Photoluminescence study of Ge layers and self-organized Ge quantum dots on Si(100) , 1996 .

[2]  G. Medeiros-Ribeiro,et al.  Electron and hole energy levels in InAs self‐assembled quantum dots , 1995 .

[3]  H. Maier,et al.  Strained state of Ge(Si) islands on Si: Finite element calculations and comparison to convergent beam electron‐diffraction measurements , 1994 .

[4]  S. Iyer,et al.  Growth and strain compensation effects in the ternary Si1-x-yGexCy alloy system , 1992 .

[5]  Akira Sakai,et al.  Ge growth on Si using atomic hydrogen as a surfactant , 1994 .

[6]  G. Abstreiter,et al.  Growth and characterization of self-assembled Ge-rich islands on Si , 1996 .

[7]  N. Ledentsov,et al.  Gain and differential gain of single layer InAs/GaAs quantum dot injection lasers , 1996 .

[8]  Brunner,et al.  Near-band-edge photoluminescence from pseudomorphic Si1-yCy/Si quantum well structures. , 1996, Physical review letters.

[9]  H. Sunamura,et al.  Island formation during growth of Ge on Si(100): A study using photoluminescence spectroscopy , 1995 .

[10]  K. Eberl,et al.  Intrinsic radiative lifetimes of InP/In0.48Ga0.52P quantum dots , 1995 .

[11]  Hans Lüth,et al.  Photoluminescence and electroluminescence of SiGe dots fabricated by island growth , 1995 .

[12]  Eaglesham,et al.  Dislocation-free Stranski-Krastanow growth of Ge on Si(100). , 1990, Physical review letters.

[13]  J. Chu,et al.  Heteroepitaxial growth of Ge on (100) Si by ultrahigh vacuum, chemical vapor deposition , 1991 .

[14]  Savage,et al.  Kinetic pathway in Stranski-Krastanov growth of Ge on Si(001). , 1990, Physical review letters.

[15]  D. Dutartre,et al.  Defect-free Stranski-Krastanov growth of strained Si1-xGex layers on Si , 1994 .