Temperature dependence of the optical transitions in Ga0.64In0.36N0.046As0.954 multiquantum wells of various widths studied by photoreflectance

Abstract

The temperature dependencies of optical transitions in as-grown Ga 0.64 In 0.36 N 0.046 As 0.954 multiple quantum wells ͑QWs͒ of various widths ͑ranging from 3.9 to 8.1 nm͒ grown at the low temperature of 375°C were studied by photoreflectance ͑PR͒. In addition to the 11H transition, which is the fundamental transition for this QW, the optical transitions between excited states ͑22H and 33H transitions, where the notation klH denotes the transition between the kth heavy-hole valence subband and the lth conduction subband͒ were clearly observed in the PR spectra. The temperature dependencies of the QW transition energies were analyzed using Varshni and Bose-Einstein expressions. It was found that with increasing temperature, both the ground-state and the excited-state transitions shift to the red without showing S-shape-type behaviors, which are typical for photoluminescence from this system. This shift does not depend on the QW width and amounts to ϳ80 meV for the 11H transition and ϳ100 meV for the 22H and 33H transitions in the temperature range of 10-300 K. These shifts are comparable to those of N-free QWs.

Pressure coefficients for direct optical transitions in MoS2, MoSe2, WS2, and WSe2 crystals and semiconductor to metal transitions

“…This technique due to its absorption-like character is an excellent tool to investigate the direct optical transitions between both ground and excited states282930. The differential-like character of PR spectroscopy allows to eliminate the background signal and detect even very weak optical transitions.…”

“…In this paper to investigate the electric band structure of MoS 2 , MoSe 2 , WS 2 , and WSe 2 under hydrostatic pressure we applied photoreflectance (PR) spectroscopy. This technique due to its absorption-like character is an excellent tool to investigate the direct optical transitions between both ground and excited states 28 29 30 . The differential-like character of PR spectroscopy allows to eliminate the background signal and detect even very weak optical transitions.…”