Polarization-sensitive opto-electronic devices based on spontaneous self-ordering in semiconductor alloys

Abstract

Spontaneous self-ordering in semiconductor alloys is not only very interesting from the fundamental point of view but can also be exploited for device applications. We report on monolithically integrated opto-electronic switching devices with high photoconductive gain. The most interesting aspect of these devices is the fact that the switching behavior depends only on the polarization angle and not on the intensity of the incoming light. The polarization sensitivity of these devices is based on the intrinsic polarization anisotropy of spontaneously ordered semiconductor crystals. The electrical output signal of the device can be switched on and off by changing the polarization direction of the incident light. We have demonstrated a switching contrast of 50 dB, a maximum sensitivity of 7 dB degree −1, and a photoconductive gain of 10 4. The switching angle is independent of the optical power over several orders of magnitude. A more sophisticated, bistable version of this detector takes advantage of the Franz–Keldysh effect (FKE). Rotating the polarization clockwise or counter-clockwise leads to a hysteresis in the output signal. We have achieved bistable switching with an adjustable hysteresis of up to 60°.