Angle-dependent differential-photovoltage spectroscopy for the characterization of a GaAs/GaAlAs based vertical-cavity surface-emitting laser structure

Abstract

Articles you may be interested inDifferential surface photovoltage spectroscopy characterization of a 1.3 μm InGaAlAs/InP vertical-cavity surfaceemitting laser structure An angle-dependent wavelength-modulated differential-photovoltage spectroscopy ͑DPVS͒ investigation has been performed at room temperature on a bare as-grown wafer of GaAs/ GaAlAs-based vertical-cavity surface-emitting laser ͑VCSEL͒ structure, designed for emitting at a wavelength near 850 nm. The differential-photovoltage ͑DPV͒ spectra exhibit both the fundamental conduction to heavy-hole excitonic transition and cavity mode plus an interference pattern related to the mirror stacks. By changing the angle of incidence in the DPV measurements the energy positions of the cavity mode and distributed Bragg reflector features show a blueshift while the excitonic transition remains unchanged. The energies of the excitonic transition and cavity mode are accurately determined from the DPV spectra. The advantages of DPVS in relation to other methods of characterizing VCSEL structures, such as surface photovoltage, photoreflectance, photocurrent, and differential photocurrent spectroscopy, are discussed. The results demonstrate considerable potential of DPVS for the nondestructive characterization of these structures at room temperature.

Surface photo-voltage characterization of GaAs/AlGaAs single quantum well laser structures grown by molecular beam epitaxy

“…The contribution to SPV from each layer in the laser structure has been determined by sequential chemical etching of the individual layers. SPV measurements have been done earlier on SQW and MQW laser structures [16][17][18]. An InGaAs/GaAs/AlGaAs SQW graded-index-of-refraction separate-confinement hetero-structure laser has been analyzed using SPV spectroscopy by Ashkenasy et al [16].…”

“…The authors have extracted important structure parameters from the simulation of the spectra. Vertical surface emitting laser (VCSEL) structures consisting of MQWs have been characterized using angle and temperature dependent SPV measurements [17,18]. However, sequential etching and subsequent measurement of SPV has not been reported in SQW laser structures so far.…”

Optimization of Bragg reflectors in AlGaAs/GaAs VCSELs

“…The central (i) region consists of several quantum wells (QWs) and two spacer layers forming a separate confinement heterostructure for efficient carrier trapping and optical confinement. To achieve optimum performance several demanding criteria need to be satisfied, which pushes growth technologies [1][2] and charac- terization method to their limits [3]. Moreover, optimization of such a structure requires a precise tuning of its main parts.…”