High quality InAs grown by liquid phase epitaxy using gadolinium gettering

Gao, H H and Krier, A and Sherstnev, V V (1999) High quality InAs grown by liquid phase epitaxy using gadolinium gettering. Semiconductor Science and Technology, 14 (5). pp. 441-445. ISSN 0268-1242

Abstract

In this paper, we report the growth of very pure InAs epitaxial layers of high quantum efficiency, by introducing the rare-earth element Gd into the liquid phase during LPE growth. We find that the carrier concentration of InAs layers can be effectively reduced to similar to 6 x 10(15) cm(-3). Also, the peak photoluminescence (PL) intensity of such layers can be considerably increased by between ten- and 100-fold compared with untreated material. We attribute this behaviour to the gettering of residual impurities and corresponding reduction of non-radiative recombination centres in the presence of Gd. Four intense sharp lines dominated the low temperature (4 K) photoluminescense spectra of Gd-treated InAs layers. The strongest two of these were found to originate from (a) bound excitons, and (b) donor-acceptor recombination, whereas the remaining two, (c) and (d), were associated with defect-related recombination. The linewidth (FWHM) of the exciton peak (a) was reduced to only 3.8 meV, which is narrower than for undoped epitaxial InAs grown by MBE or MOVPE.