Laterally Biased Quantum-Well Infrared Photodetectors Operating at Room Temperature With Low Dark Currents

The technology of quantum-well infrared photodetectors has been used to fabricate focal plane arrays as the active element of infrared cameras. These arrays must be cooled down to 77 K due to the large dark current that they exhibit at higher operating temperatures. Among the different alternatives proposed to overcome this drawback, the lateral conduction scheme has been successfully employed in quantum-dot and dot-in-a-well detectors to increase their operating temperature. In these devices, the photocurrent is collected by means of two lateral Ohmic contacts on each side of an undoped quantum well and is swept out via a lateral bias voltage. However, this lateral-carrier-transport scheme has not yet been applied to the mature technology of the GaAs/(Al,Ga)As quantum-well infrared photodetectors. We demonstrate two mechanisms to develop laterally biased quantum-well infrared photodetectors. The resulting devices exhibit high differential resistance as well as low dark current values and clear infrared absorption peaks at 300 K, in good agreement with the results of numerical simulations. This work demonstrates the viability of the laterally biased structures for future developments of room temperature focal plane arrays.