Reduced temperature dependence of refractive-index in TlInGaAs quaternary alloys grown on InP substrates

Abstract

Refractive-index dispersion for the TlInGaAs quaternary alloys, grown on (100) InP substrates by gas-source molecular-beam epitaxy, has been measured at temperatures from 290 to 350 K in the photon-energy range of 1.2–2.0 eV by using spectroscopic ellipsometry. The temperature coefficient of the refractive-index decreases with increasing Tl composition. The result corresponds to the already reported reduced temperature dependence of the band-gap energy for the TlInGaAs because of the alloy of semiconductor InGaAs and semimetal TlAs. The result also agrees with the recently reported small temperature-variation of the lasing-wavelength for the TlInGaAs/InP laser diodes.

Refractive index of TlGaAs

“…As can be seen in the figure, the temperature coefficient tends to increase slightly with Tl content. This ten- dency is opposite to the case of TlInGaAs grown on InP substrates, for which Imada et al [8] claimed that dn/dT decreases with increasing Tl content.…”

An approach to temperature‐insensitive band gap – The InGaGdN case

“…Temperature‐insensitivity in the photoluminescence (PL) peak position is one of the most attractive goals for the infrastructure in the light communication field. Several attempts to achieve the goal are reported 1–6. One solution is to introduce the heavy elements (T$\ell $ 1, 3 and Bi 4), of which compounds present the opposite behavior in the temperature dependence in the PL peak position relative to that of the major materials, in the matrix to produce the alloy.…”