Room Temperature Observation of the Energy Levels of Mid-Infrared Quantum Well Lasers using Fourier Transform Infrared-Surface Photovoltage Spectroscopy

Abstract

At room temperature, we demonstrate an unambiguous detection of the ground- and excited-state transitions of mid-infrared GaInSb/AlGaInSb type I quantum well (QW) lasers grown on GaAs using a new technique based on Fourier transform infrared surface photovoltage spectroscopy. It is found that none of the currently established spectroscopic techniques is able to detect even the ground state transition of these mid-infrared QW lasers at room temperature. The spectroscopic results are in reasonable agreement with the laser emission spectra at low temperatures.

A vector model for analysing the surface photovoltage amplitude and phase spectra applied to complicated nanostructures

“…Surface photovoltage (SPV) spectroscopy is a powerful non-destructive and contactless characterization technique, which has been successfully applied for characterization of different semiconductor bulk materials and nanostructures [1][2][3][4][5][6]. Due to its high sensitivity this technique can give important information about the electronic structure and optical properties of nanostructures even at room temperature [1,7,8].…”

A Method of Obtaining Simultaneous Complementary Spectroscopic Information on Self-Assembled Quantum Dots

“…Indeed, in a recent article we showed that in certain narrow-gap quantum well (QW) samples, it is in fact the SPS that provides by far the most useful information, as compared to PR or PL. 23) Huang et al 24) drew a similar conclusion for a verticalcavity surface-emitting laser structure. For usefulness across a wide range of systems, and because we do not always know in advance which technique may turn out to be the most useful, it is, therefore, highly valuable to be able to investigate any given sample with all three techniques at the same time.…”

Room temperature spectroscopic characterization of mid-infrared GaInSb quantum-well laser structures

“…Note, it is often assumed in SPS that R varies so slowly with ν that the [1−R] term can be neglected. However, many MIR laser structures can show strong interference-related oscillations in the QW region of the R spectra [8], as is found here, and it is necessary to measure the absolute R, as described in [9]. As device emission wavelengths are pushed further into the MIR, it becomes increasingly inefficient to use diffraction-grating-based SPS, due to fundamental spectroscopic and physical limitations [10].…”

“…We recently developed an SPS technique that uses instead the more efficient Fourier transform infrared (FTIR) interferometer and demonstrated it on MIR laser structures similar to those of [2,6] showing that FTIR-SPS was capable of fully characterizing such structures at RT. Full details of the FTIR-SPS technique are given in [8,9]. It has similarities to conventional SPS [7] except that broadband output light from the FTIR is directed onto the sample which, acting as a detector, generates an open-circuit voltage interferogram from which the SPS spectrum is obtained by conventional FT.…”