Abstract Thick metamorphic buffers are considered indispensable for III‐V semiconductor heteroepitaxy on large lattice and thermal‐expansion mismatched silicon substrates. However, III‐nitride in conventional GaN‐on‐Si high electron mobility transistors (HEMT) impose a substantial thermal resistance, deteriorating device efficiency lifetime by throttling heat extraction. To circumvent this, systematic methodology the direct growth of GaN after AlN nucleation layer six‐inch substrates is...

Abstract For the growth of low-defect crack-free GaN heterostructures on large-area silicon substrates, compositional grading AlGaN is a widely adapted buffer technique to restrict propagation lattice-mismatch induced defects and balance thermal expansion mismatch-induced tensile stress. So far, consolidation design strategy such step-graded buffers has been impaired by incomplete understanding effect individual parameters mechanical microstructural properties epilayers. Herein, we have...

Abstract Ohmic contacts to wide bandgap nitrides have been realised, but little is known about their behaviour at low temperatures. To address this, an established Ti/Al/Ti/Au contact stack on AlGaN/GaN heterostructures has characterised from 320 K 80 K. Two structures were investigated, with very similar ambient 2DEG transport characteristics despite difference in AlGaN barrier thickness and composition. This allowed for direct comparison of across different heterostructures. Upon annealing...

Abstract Reconfigurable memristors featuring neural and synaptic functions hold great potential for neuromorphic circuits by simplifying system architecture, cutting power consumption, boosting computational efficiency. Building upon these attributes, their additive manufacturing on sustainable substrates further offers unique advantages future electronics, including low environmental impact. Here, exploiting the structure–property relationship of inkjet‐printed MoS 2 nanoflake‐based...

The performance of transistors designed specifically for high-frequency applications is critically reliant upon the semi-insulating electrical properties substrate. suspected formation a conductive path radio frequency (RF) signals in highly resistive (HR) silicon substrate itself has been long held responsible suboptimal efficiency as-grown GaN high electron mobility (HEMTs) at higher operating frequencies. Here, we reveal that not one but two discrete channels distinguishable by their...

Abstract In this article, porous GaN distributed Bragg reflectors (DBRs) were fabricated by epitaxy of undoped/doped multilayers followed electrochemical etching. We present backscattered electron scanning microscopy (BSE-SEM) for sub-surface plan-view imaging, enabling efficient, non-destructive pore morphology characterization. mesoporous DBRs, BSE-SEM images the same branching pores and Voronoi-like domains as transmission microscopy. microporous micrographs dominated first layer features...

A generalized threshold voltage model based on two-dimensional Poisson analysis has been developed for SOI/SON MOSFETs. Different short channel field effects, such as fringing fields, junction-induced lateral fields and substrate are carefully investigated, the related drain-induced barrier-lowering effects incorporated in analytical model. Through model-based simulation, roll-off subthreshold slope both structures compared different operational structural parameter variations. Results of...

Effective light extraction from optically active solid-state spin centers inside high-index semiconductor host crystals is an important factor in integrating these pseudo-atomic wider quantum systems. Here, we report increased fluorescent collection efficiency laser-written nitrogen-vacancy (NV) bulk diamond facilitated by micro-transfer printed GaN solid immersion lenses. Both laser-writing of NV and transfer printing micro-lens structures are compatible with high spatial resolution,...

The scanning capacitance microscope (SCM) is a powerful tool to characterise local electrical properties in GaN-based high electron mobility transistor (HEMT) structures with nanoscale resolution. We investigated the experimental setup and imaging conditions optimise SCM contrast. As setup, we show that desired tip should be sharp (e.g., radius of ≤25nm) its coating made conductive doped diamond. Most importantly, spring constant large achieve stable tip-sample contact. selected positioned...

We demonstrate the back-end integration of broadband, high-NA GaN micro-lenses by micro-assembly onto non-native semiconductor substrates. developed a highly parallel micro-fabrication process flow to suspend micron scale plano-convex lens platelets from 6" Si growth wafers and show their subsequent transfer-printing integration. A targeted at producing unbowed epitaxial was combined with optimisation etching volume in order produce flat devices for printing. Lens structures were fabricated...

III-nitride materials, such as GaN and its alloys, are essential for modern microelectronics optoelectronics due to their unique properties. Focused ion beam (FIB) techniques play a crucial role in prototyping characterization at the micro- nanoscale. However, conventional FIB milling with Ga ions presents challenges, including surface amorphization point defect introduction, prompting exploration of alternative sources. Xenon-based inductively coupled plasma or has emerged promising...

Distributed Bragg reflectors (DBRs) based on alternating layers of porous and non-porous GaN have previously been fabricated at the wafer-scale in heteroepitaxial grown sapphire substrates. Porosification is achieved via electrochemical etching highly Si-doped layers, etchant accesses n+-GaN through nanoscale channels arising threading dislocations that are ubiquitous growth process. Here, we show same process applies to multilayer structures silicon The reflectance resulting DBRs depends...

GaN-on-Si has become a useful fabrication route for many GaN devices and applications, but the mechanical stress incorporated throughout material stack can impact viability of this approach. The transfer printing membrane devices, promising emerging technology, is most effective with flat membranes, in practice structures released from their Si substrate are highly bowed due to strain epitaxial nitride stack. Our approach uses optical profiles wafers membranes as inputs inferring state by...

Transfer printing integration of planar membrane devices on photonic and electronic circuits is becoming a well established technology. Typical systems incorporate single layer printed into full contact with the host substrate. In this work we present an advanced transfer print system that enables optical in non-planar geometries allows in-situ monitoring devices. We show micro-resonators air-clad whispering gallery modes coupled to on-chip waveguides, inverted device three dimensionally...

Herein, the use of cathodoluminescence (CL) hyperspectral mapping in quantification AlGaN alloy composition graded buffer structures is explored. The takes advantage known parabolic dependence bandgap on allowing near‐band‐edge (NBE) emission energy recorded from CL to be converted a composition. proposed method first applied cleaved cross‐sections two nominally step‐graded each containing five layers with different compositions. By comparing compositions obtained those calculated using...

Understanding the growth mechanisms of III-nitride nanowires is great importance to realise their full potential.

This paper presents the growth of thin GaN capping layers on standard AlGaN HEMT structures. It has been found that reliable (≤5nm) by organometallic vapour phase epitaxy is challenging as unstable at high temperatures even in atmospheres with ammonia partial pressure. To overcome this challenge a strategy based controlled desorption adopted. By intentionally growing thicker than desired and controlling during cool down after it feasible to reliably grow quality specific target thickness....

Reconfigurable memristors featuring neural and synaptic functions hold great potential for neuromorphic circuits by simplifying system architecture, cutting power consumption, boosting computational efficiency. Their additive manufacturing on sustainable substrates offers unique advantages future electronics, including low environmental impact. Here, exploiting structure-property relationship of MoS2 nanoflake-based resistive layer, we present paper-based, inkjet-printed, reconfigurable...

Laser-written Nitrogen Vacancy (NV−) centers are combined with transfer-printed GaN micro-lenses to increase fluorescent light collection by reducing total internal reflection at the planar diamond interface. We find a 2x improvement of using 0.95 NA air objective room temperature, in agreement FDTD simulations. The nature transfer print leads better performance lower Numerical Aperture (NA) collection, as confirmed results 0.5NA which show greater than 5x. approach is attractive for...

Hyperspectral scanning capacitance microscopy (SCM) measures dC/dV−V spectra at every XY location of a semiconductor sample surface area. We report its application to GaN-based high electron mobility transistor (HEMT) structures map threshold voltage (Vth) the nanoscale. The consistency between conventional SCM data and hyperspectral set same area on HEMT provides evidence for reliability SCM. developed method extract Vth distribution across structure nanoscale from set. reveals that most...

Room temperature quantum emitters have been reported in aluminum nitride grown on sapphire, but until now they not observed epilayers silicon. We report that epitaxial silicon by either plasma vapor deposition or metal-organic phase epitaxy contains point-like the red to near-infrared part of spectrum. study photon statistics and polarization emission at a wavelength 700–750 nm, showing signatures quantized electronic states under pulsed CW optical excitation. The discovery material...

Thick metamorphic buffers are perceived to be indispensable for the heteroepitaxial integration of III-V semiconductors on silicon substrates with large thermal expansion and lattice mismatches. However, III-nitride in conventional GaN-on-Si high electron mobility transistor (HEMT) heterostructures impose a substantial resistance, throttling heat extraction, which reduces device efficiency lifetime. Herein, bypassing buffer, we demonstrate direct growth GaN after AlN nucleation layer by...