Photoluminescence Studies of [(CdSe) 1 (ZnSe) 2 ] 9 -ZnSeTe Multiple Quantum Wells Under High Pressure
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Z.P. WANG, Z.X. LIU*, H.X. HAN*, J.Q. ZHANG*, G.H. LI*, Z.L. PENG* AND S.X. YUAN** *Institute of Semiconductors, Academia Sinica, Beijing 100083, P. 0. Box 912, China "**ShanghaiInstitute of Technical Physics, Academia Sinica, Shanghai 200083, China
ABSTRACT We have performed photoluminescence (PL) measurements at liquid nitrogen temperature under high pressure up to 5.5 GPa and in the temperature range 10-300 K at atmospheric pressure on {(ZnSe) 3o(ZnSeo. 92Teo.os) 3o(ZnSe) 3 o[(CdSe)i(ZnSe) 219} x5 multiple quantum wells. The PL peaks, EB, E, and Ew corresponding to the band edge luminescence in ZnSe barrier layer, the transitions from the first conduction subband to the heavy-hole subband in ZnSeo. 92Teo.08 layers and [(CdSe)1 (ZnSe) 2] 9 ultra short period superlattice quantum well (SPSLQW) layers have been observed. Experimental results show that ZnSe0 .92Te0 .08/ZnSe forms a type-I superlattice (SL) in contrast to the type-II ZnSe/ZnTe SL. The pressure coefficients of the EB, E, and Ew exciton peaks have been determined as 67, 63 and 56 meV/GPa, respectively. With increasing temperature (or pressure), the E, peak-intensity drastically decreases which is attributed to the thermal effect (or the appearance of many defects in ZnSe0 .92Te0 08 . under higher pressure). Key words: II-VI compound, superlattice, quantum well, photoluminescence, pressure INTRODUCTION In recent years, considerable attention has been focused on 1I-VI semiconductors with wide energy gaps because of their application in blue-green range opto-electronic device development, such as the fabrication of blue-green laser diodes based on ZnCdSe/ZnSe single (multiple) quantum well(s) 12 . However, only Znl.xCd.Se/ZnSe superlattices with x
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