Optical upconverter with integrated heterojunction phototransistor and light-emitting diode

Abstract

We report an optical upconversion device that converts input 1.5μm light to output 0.87μm light with a built-in gain mechanism. The device consists of an InGaAs∕InP heterojunction phototransistor (HPT) integrated with a GaAs∕AlGaAs light-emitting diode (LED) by wafer fusion process. Incoming 1.5μm optical radiation is absorbed by the HPT, generating an amplified photocurrent. The resultant photocurrent drives the LED that emits at 0.87μm, which could be detected by a conventional silicon charge-coupled device. Upconversion is demonstrated at room temperature with a gain of 20 from the HPT and an overall external upconversion efficiency of 0.07W∕W.

Near-infrared to visible light optical upconversion by direct tandem integration of organic light-emitting diode and inorganic photodetector

“…[1][2][3][4] The near infrared optical upconverters in the eye-safe region around 1.5 m are of particular interest because of its many potential applications such as night vision, range finding, homeland security, and semiconductor wafer inspection. [5][6][7][8][9] Monolithic integration of a detector and an emitter using direct epitaxial growth 1,5 or wafer fusion technique [6][7][8] has been demonstrated. In monolithic devices by direct epitaxial growth, the band gap difference between the active region of a light-emitting device and the active region of the photodetector is highly restricted due to stringent lattice-matching requirements imposed by the uninterrupted epitaxial growth of the various layers in the devices.…”

Recent advances with optical upconverters made from all-organic and hybrid materials

“…Early upconverters were made with III-V inorganic compound semiconductors via epitaxial growth or wafer fusion [14,15]. A fundamental issue for monolithic devices involves the need for lattice match between different layers, especially at the photodetector/light-emitting interface.…”

Performance optimization of Pnp InGaAs/InP heterojunction phototransistors

“…However, the HPTs also have some drawbacks that limit their applications in optoelectronic systems. There have been several reports on performance improvement for typical HPT, for example, a thin, low-doped N-InP layer can be grown between the emitter and base of a N-InP/p?-In 0.53 Ga 0.47 As/n-In 0.53-Ga 0.47 As HPT, which can reduce the recombination current at the hetero-interface and then reduce the dark current of the device [11]. The optimization of the collector region is also important because the maximum current density that the device can handle is very sensitive to the collector doping concentration [12,13].…”