Operation of a novel hot-electron vertical-cavity surface-emitting laser

Abstract

The hot Electron Light Emission and Lasing in Semiconductor Heterostructure devices (HELLISH-i) is novel surface emitter consisting of a GaAs quantum well (QW), within the depletion region, on the n side of GaiA1As p-n junction. It utilises hot electron transport parallel to the layers and injection of hot electron hole pairs into the quantum well through a combination of mechanisms including tunnelling, thermionic emission and diffusion of lucky' carriers. Super Radiant HELLISH-i is an advanced structure incorporating a lower distributed Bragg reflector (DBR). Combined with the finite reflectivity of the upper semiconductor-air interface reflectivity it defines a quasi-resonant cavity enabling emission output from the top surface with a higher spectral purity. The output power has increased by two orders of magnitude and reduced the full width at half maximum (FWHM) to 2Onm. An upper DBR added to the structure defines HELLISH-VCSEL which is currently the first operational hot electron surface emitting laser and lases at room temperature with a l.5nm FWHM. In this work we demonstrate and compare the operation of UB-HELLISH-l and HELLISH-VCSEL using experimental and theoretical reflectivity spectra over an extensive temperature range.

Temperature dependence of the threshold electric field in a hot electron VCSEL

“…The threshold carrier density ðn th Þ shown in Fig. 9b is calculated as a function of temperature using the values of quasi-Fermi levels in (5). The parameters used in the analysis are given in Table 2.…”

The operation of a novel optically modulated vertical‐cavity semiconductor optical amplifier with wavelength converting functionality

“…We have previously demonstrated several novel longitudinal transport surface-emitting HELLISH (hot electron light emitting and lasing in semiconductor heterojunction) devices [7][8][9][10]. All of these devices benefit from very simple fabrication in that they require only two point contacts (n-type) diffused through all the layers.…”