Hypothetical band diagram of a material with single-carrier (electron) avalanche multiplication. The successful ionization event (a) is caused by the primary electron 1, which transfers its excess energy E k to the electron 2 in the VB that results in creation of the secondary electron-hole pair 2–2′. The distinctive feature of this band structure is a limited width of the valence band (solid vs dashed line) that precludes holes (b) from gaining energy sufficiently high for the secondary electron-hole pair production.
Chalcopyrite structure of CuAlSe2.
Band structure (a) of the CuAlSe2 chalcopyrite semiconductor plotted along the high-symmetry k-points in tetragonal Brillouin zone (b). The notable feature is a separation of the uppermost valance band from the rest of valance states. The energies are plotted relative to the Fermi energy E F. The panel (c) illustrates p-d hybridization resulted in appearance of the VB gap.
Band structure of ternary chalcopyrite compounds. The notable feature is the separation of the uppermost valance band from the rest of valance states observed in CuAlTe2 (a) and CuGaSe2 (c), but not in AgAlSe2 (b). The inset on panel (b) shows schematically the p-d hybridization in AgAlSe2 that results in vanishing of the gap between bonding and antibonding states forming the upper VB. The energies are plotted relative to the Fermi energy E F.
Structure of the Cu16Al9Ga7Se32 random alloy.
Band structure of Cu16Al9Ga7Se32 random alloy plotted relative to the Fermi energy.
Atom-specific projected density of states for the Cu16Al9Ga7Se32 random alloy.
Proposed device structure and energy-band diagram of Cu(AlGa)Se2 APD under a reverse bias V R.
Energies (eV) of valence atomic orbitals for selected elements obtained with a relativistic local spin density approximation. The values in numerator and denominator correspond to the electron spin up/down.
Lattice parameters a and c (Å) and the optical energy gap E g(eV) of chalcopyrite compounds studied here.
Article metrics loading...
Full text loading...