LONG-LIVED EXCITED IMPURITY STATES IN DIAMOND-LIKE SEMICONDUCTORS

The lifetime of charge carriers in the lowest excited states of some i mpurities of groups III and V in diamond, silicon, and germanium can b e several (four to six) orders of magnitude longer that the lifetime o f free carriers. Accumulation of carriers in these long-lived states m ay give rise to several new effects, such as hopping photoconductivity via long-lived excited states of impurities in de and microwave elect ric fields, slow relaxation of induced absorption, and infrared absorp tion at energies lower than the impurity ionization energy. (C) 1997 A merican Institute of Physics.