Photoluminscence and Photoluminescence Excitation Spectroscopy Study of Thin GaInAs/InP Quantum Wells

Photoluminescence excitation spectroscopy (PLE) has been widely applied to reveal information about the subband structure of quantum wells (QWs). PLE essentially probes the intersubband absorption in the well, which cannot be probed in transmission because of the low absorbances of single QWs. PLE is a standard characterization technique for AIGaAs/GaAs QWs due to the availability of tunable dye lasers as excitation sources in the AIGaAs/GaAs spectral regime (e.g. ref.[1]). There have been very few PLE studies on GaInAs/InP QWs because in this spectral regime there are no laser dyes commercially available. Kodama et al. [2] and Sauer et al. [3] have studied GaInAs/InP multiple QWs and observed transitions from the first three heavy and the first two light hole subbands to the respective electron subbands. Skolnick et al.[4,5], Sauer et al.[6,7], Razeghi et al. [8,9], and Temkin et al.[10] have studied GaInAs/InP single QWs, and observed transitions from the first five heavy and the first three light hole subbands to the respective electron subbands. Skolnick et al. [5] have tentatively assigned a feature in their spectra to absorption involving the first heavy hole subband and the InP (barrier) conduction band. In this study PLE spectra from extremely thin Gag0 47ln0 53AS /InP single QWs are investigated. The PL spectra from these samples exhibit narrow, intense multiplets, which have been attributed to recombination in regions of the wells, differing in width by single monolayers [11].