Near-Infrared Intersubband Photodetection in GaN/AlN Nanowires

Abstract

Intersubband optoelectronic devices rely on transitions between quantum-confined electron levels in semiconductor heterostructures, which enables infrared (IR) photodetection in the 1-30 μm wavelength window with picosecond response times. Incorporating nanowires as active media could enable an independent control over the electrical cross-section of the device and the optical absorption cross-section. Furthermore, the three-dimensional carrier confinement in nanowire heterostructures opens new possibilities to tune the carrier relaxation time. However, the generation of structural defects and the surface sensitivity of GaAs nanowires have so far hindered the fabrication of nanowire intersubband devices. Here, we report the first demonstration of intersubband photodetection in a nanowire, using GaN nanowires containing a GaN/AlN superlattice absorbing at 1.55 μm. The combination of spectral photocurrent measurements with 8-band k·p calculations of the electronic structure supports the interpretation of the result as intersubband photodetection in these extremely short-period superlattices. We observe a linear dependence of the photocurrent with the incident illumination power, which confirms the insensitivity of the intersubband process to surface states and highlights how architectures featuring large surface-to-volume ratios are suitable as intersubband photodetectors. Our analysis of the photocurrent characteristics points out routes for an improvement of the device performance. This first nanowire based intersubband photodetector represents a technological breakthrough that paves the way to a powerful device platform with potential for ultrafast, ultrasensitive photodetectors and highly efficient quantum cascade emitters with improved thermal stability.

Three-dimensional hierarchical semi-polar GaN/InGaN MQW coaxial nanowires on a patterned Si nanowire template

“…27,28 Therefore, the semi-polar growth of GaN/InGaN MQWs is the most preferred and is currently actively studied for GaN-based optical applications in leading laboratories. [29][30][31][32][33][34] In this work, we fabricate the next-generation 3-D semipolar GaN/InGaN hierarchical NWs grown on a Si NWtemplate and characterize their optical properties. The morphology of the Si NWs is controlled with metal-assistedchemical-etching (MACE) together with the morphology of the GaN NWs grown by metal-organic chemical vapor deposition (MOCVD).…”

Correlated and in-situ electrical transmission electron microscopy studies and related membrane-chip fabrication

“…In general, the photocurrent of GaN NW photodetectors presents a sub-linear dependence on the illumination power [28,[34][35][36][37]. However, Spies et al [38] demonstrated that such devices can behave as linear detectors, depending on the direction of the applied bias and the NW diameter.…”

Nanowire photodetectors based on wurtzite semiconductor heterostructures

“…Using GaN/AlN (2 nm / 3 nm) nanowire heterostructures with ISB absorption around 1.55 µm, a single nanowire QWIP has been demonstrated [189]. The spectral response of the detector was obtained by measuring the photocurrent induced by various laser diodes operating at different wavelengths along the near-IR spectrum, as shown in figure 21.…”