Acceptor identification using magnetophotoluminescence of bound exciton states in InSb

Photoluminescence measurements were performed on Czochralski-grown indium antimonide samples in magnetic fields up to 7 T using a cryogenically cooled interferometer. Principal acceptor bound exciton luminescence and corresponding two-hole transitions (THT) were observed for both p-type and n-type samples. THT corresponding to the ${2S}_{3/2}$ excited states of the acceptor were observed in Cd-doped and Ge-doped InSb samples, and the photoluminescence of the two acceptors can be distinctly resolved with a separation of $1.6{\mathrm{cm}}^{-1}$ at 1 T. For magnetic fields above 1 T, excitations to the ${2P}_{5/2}$ and ${3S}_{3/2}$ states were also observed. The Zeeman splittings for all of the THT were mapped as a function of magnetic field, and zero-field energies for the acceptor excited states ${2S}_{3/2}\left({\Gamma }_8\right),$ ${3S}_{3/2}\left({\Gamma }_8\right),$ ${2P}_{5/2}\left({\Gamma }_8\right),$ and ${2P}_{5/2}\left({\Gamma }_7\right)$ were measured for both the Ge and Cd acceptors. Using the energy separation of the principal bound exciton luminescence and the THT luminescence from the ${2P}_{5/2}\left({\Gamma }_7\right)$ excited state along with the theoretically calculated binding energy for the ${2P}_{5/2}\left({\Gamma }_7\right)$ state, acceptor binding energies of 79.2 and $80.5{\mathrm{cm}}^{-1}$ were established for Ge and Cd, respectively. The THT for the ${2S}_{3/2}\left({\Gamma }_8\right)$ excited state of a third, unidentified acceptor ${(A}_3)$ were observed, and a binding energy of $106.9{\mathrm{cm}}^{-1}$ was determined.