Optical characterization of Si‐doped metamorphic InGaAs with high indium content

Abstract

The optical properties of Si‐doped metamorphic InGaAs layers with electron concentration in the range of 3 × 1016 to 6 × 1018 cm−3 are investigated in detail. The 10 K photoluminescence spectrum of lightly doped metamorphic In0.81Ga0.19As showed a narrow sharp peak at 546 meV with a full width at half maximum of 17.1 meV, comparable to that of InP‐lattice‐matched In0.53Ga0.47As, which is an evidence of the good crystalline quality. In the temperature range of 10–300 K, only band‐to‐band transition was observed in both lightly Si‐doped In0.53Ga0.47As and In0.81Ga0.19As, while the band‐to‐band emission was overlapped by multiple transitions in heavily Si‐doped In0.81Ga0.19As. A marked blueshift and significant increase in the linewidth of photoluminescence at high doping level were observed due to the enhanced band filling as well as many body effects in the heavily Si‐doped high indium content material. The alloy disorder, caused by heavy Si doping, seriously degrades the crystalline quality and immensely reduces the possibilities of radiative recombination in In0.81Ga0.19As.

Low-Temperature Growth of InGaAs Quantum Wells Using Migration-Enhanced Epitaxy

“…In sample B, the Raman peak at 233 cm −1 (labeled as "d"), is attributed to the LO mode of InAs, while the peak at 262 cm −1 (labeled as "f"), is attributed to the LO mode of GaAs, consistent with reports in the literature [40]. The peak between 240 and 250 cm −1 , labeled "e", is consistent with disordered activated optical phonons, also reported in previous studies [40,41]. The appearance of the peak labeled "e" in sample B indicates a considerable degree of atomic disorder within the InGaAs/InAlAs MQWs grown at low temperatures using the conventional MBE mode.…”

“…The compressive strain within the InAs superlattice results in a Raman shift towards higher wavenumbers, whereas the tensile strain in GaAs leads to a shift towards lower wavenumbers. The strain-induced opposing shifts ultimately result in the convergence and merging of the InAs and GaAs LO peaks into the observed 255 cm −1 Raman peak [39,40]. In sample B, the Raman peak at 233 cm −1 (labeled as "d"), is attributed to the LO mode of InAs, while the peak at 262 cm −1 (labeled as "f"), is attributed to the LO mode of GaAs, consistent with reports in the literature [40].…”

“…The strain-induced opposing shifts ultimately result in the convergence and merging of the InAs and GaAs LO peaks into the observed 255 cm −1 Raman peak [39,40]. In sample B, the Raman peak at 233 cm −1 (labeled as "d"), is attributed to the LO mode of InAs, while the peak at 262 cm −1 (labeled as "f"), is attributed to the LO mode of GaAs, consistent with reports in the literature [40]. The peak between 240 and 250 cm −1 , labeled "e", is consistent with disordered activated optical phonons, also reported in previous studies [40,41].…”