Effect of sidewall reflector on current versus light output in a pnpn vertical-to-surface transmission electrophotonic device with a vertical cavity

The authors experimentally study the effect of a sidewall reflector on current versus light-output characteristics in a pnpn vertical-to-surface-transmission electrophotonic device with a vertical cavity. The distributed Bragg reflectors that form the vertical cavity for laser oscillation and the sidewall reflector retain spontaneously emitted photons in the optical cavity, and only the photons that have the resonance wavelength of the vertical cavity are emitted. As a result, spontaneously emitted photons are absorbed and the carriers are regenerated; that is, the injected carriers are converted to light, and spontaneous emission is reconverted to carriers. As a result of photon recycling of spontaneous emission, threshold reduction is expected. Threshold reduction by at least a factor of 4 is obtained with a device that has the sidewall reflector.>