LUMINESCENCE OF DEEP PHOSPHORUS AND ARSENIC IMPURITIES IN ZNSE AT HIGH-PRESSURE

High-pressure photoluminescence (PL) is reported for bulk and thin-fil m ZnSe containing 10(18)-10(19) cm(-3) P and As accepters using a cryo genic (4-300 K) diamond-anvil cell to 55 kbar. We focus on the deep PL bands in the red and green regions of the visible spectrum; the red e mission bands (1-atm peaks at similar to 6000 A in ZnSe:P and similar to 7000 A in ZnSe:As) are thought to stem from C-3 upsilon-distorted a cceptor sites. With increasing pressure in the range studied, the peak energies of all the deep bands approach but do not cross the ZnSe ban d gap. The average deformation potential of the valence edge relative to the P or As deep levels attributed to C-3 upsilon sites is -1.2+0.3 eV. The negative sign is confirmed by thermal quenching data at diffe rent pressures in ZnSe:P. These results imply that with pressure the v alence edge shifts to higher energy, causing deep acceptor states to b ecome less stable. We also observe under pressure strong transfer of o scillator strength from red to green emission, and several deep bands. However, since the shallow acceptor-bound exciton PL is not enhanced, we conclude that a deep-to-shallow transition has not occurred within the pressure range studied.