Optically-switched resonant tunneling diodes

The resonant-tunneling diode (RTD) has been studied for many years because of its potential utility in high speed switching applications and compressed functionality circuits. 172 As a result of these investigations, the essential electronic characteristics of the RTD are now understood. However, the RTD's optoelectronic properties and its potential use in optical communication systems have not received much attention. With few exceptions,3 the optical investigations performed on the RTD have been directed towards understanding the charge build up characteristics within the quantum well (QW).4 In contrast, we have fabricated and characterized a series of InPand GaAs-based double barrier heterostructures (DB) that contain thick, undoped photon-absorption layers to maximize optical interactions. This new device, termed an optically-switched resonant-tunneling diode (ORTD), operates at room temperature and exhibits a 500 mV output voltage swing in response to a 0.2 mWinput optical signal at 880 nm.