Ni Haiqiao

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Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 May 2017 in Discover Nano

Journal Article

Bright Single-Photon Source at 1.3 μm Based on InAs Bilayer Quantum Dot in Micropillar

A pronounced high count rate of single-photon emission at the wavelength of 1.3 μm that is capable of fiber-based quantum communication from InAs/GaAs bilayer quantum dots coupled with a micropillar (diameter ~3 μm) cavity of distributed Bragg reflectors was investigated, whose photon extraction efficiency has achieved 3.3%. Cavity mode and Purcell enhancement have been observed clearly in microphotoluminescence spectra. At the detection end of Hanbury-Brown and Twiss setup, the two avalanched single-photon counting modules record a total count rate of ~62,000/s; the time coincidence counting measurement demonstrates single-photon emission, with the multi-photon emission possibility, i.e., g 2(0), of only 0.14.

30 August 2016 in Discover Nano

Journal Article

Telecommunication Wavelength-Band Single-Photon Emission from Single Large InAs Quantum Dots Nucleated on Low-Density Seed Quantum Dots

Single-photon emission in the telecommunication wavelength band is realized with self-assembled strain-coupled bilayer InAs quantum dots (QDs) embedded in a planar microcavity on GaAs substrate. Low-density large QDs in the upper layer active for ~1.3 μm emission are fabricated by precisely controlling the indium deposition amount and applying a gradient indium flux in both QD layers. Time-resolved photoluminescence (PL) intensity suggested that the radiative lifetime of their exciton emission is 1.5~1.6 ns. The second-order correlation function of g 2(0) < 0.5 which demonstrates a pure single-photon emission.

8 May 2013 in Discover Nano

Journal Article

GaAs-based resonant tunneling diode (RTD) epitaxy on Si for highly sensitive strain gauge applications

As a highly sensitive strain gauge element, GaAs-based resonant tunneling diode (RTD) has already been applied in microelectromechanical system (MEMS) sensors. Due to poor mechanical properties and high cost, GaAs-based material has been limited in applications as the substrate for MEMS. In this work, we present a method to fabricate the GaAs-based RTD on Si substrate. From the experimental results, it can be concluded that the piezoresistive coefficient achieved with this method reached 3.42 × 10⁻⁹ m²/N, which is about an order of magnitude higher than the Si-based semiconductor piezoresistors.

17 December 2012 in Materials

Journal Article

Optimization of the GaAs-on-Si Substrate for Microelectromechanical Systems (MEMS) Sensor Application

Resonant Tunneling Diodes (RTD) and High Electron Mobility Transistor (HEMT) based on GaAs, as the piezoresistive sensing element, exhibit extremely high sensitivity in the MEMS sensors based on GaAs. To further expand their applications to the fields of MEMS sensors based on Si, we have studied the optimization of the GaAs epitaxy layers on Si wafers. Matching superlattice and strain superlattice were used, and the surface defect density can be improved by two orders of magnitude. Combing with the Raman spectrum, the residual stress was characterized, and it can be concluded from the experimental results that the residual stress can be reduced by 50%, in comparison with the original substrate. This method gives us a solution to optimize the epitaxy GaAs layers on Si substrate, which will also optimize our future process of integration RTD and HEMT based on GaAs on Si substrate for the MEMS sensor applications.

21 February 2018 in Discover Nano

Journal Article

Elimination of Bimodal Size in InAs/GaAs Quantum Dots for Preparation of 1.3-μm Quantum Dot Lasers

The device characteristics of semiconductor quantum dot lasers have been improved with progress in active layer structures. Self-assembly formed InAs quantum dots grown on GaAs had been intensively promoted in order to achieve quantum dot lasers with superior device performances. In the process of growing high-density InAs/GaAs quantum dots, bimodal size occurs due to large mismatch and other factors. The bimodal size in the InAs/GaAs quantum dot system is eliminated by the method of high-temperature annealing and optimized the in situ annealing temperature. The annealing temperature is taken as the key optimization parameters, and the optimal annealing temperature of 680 °C was obtained. In this process, quantum dot growth temperature, InAs deposition, and arsenic (As) pressure are optimized to improve quantum dot quality and emission wavelength. A 1.3-μm high-performance F-P quantum dot laser with a threshold current density of 110 A/cm2 was demonstrated.

27 April 2021 in Nanomaterials

Journal Article

Wet-Etched Microlens Array for 200 nm Spatial Isolation of Epitaxial Single QDs and 80 nm Broadband Enhancement of Their Quantum Light Extraction

Uniform arrays of three shapes (

g a u s s

h a t

, and

p e a k

) of GaAs microlenses (MLs) by wet-etching are demonstrated, ∼200 nm spatial isolation of epitaxial single QDs embedded (

λ

: 890–990 nm) and broadband (

Δ λ \sim 80

nm) enhancement of their quantum light extraction are obtained, which is also suitable for telecom-band epitaxial QDs. Combined with the bottom distributed Bragg reflector, the

h a t

-shaped ML forms a cavity and achieves the best enhancement: extraction efficiency of 26%, Purcell factor of 2 and single-photon count rate of

7 \times 10^{6}

counts per second at the first lens; while the

g a u s s

-shaped ML shows a broader band (e.g., longer

λ

) enhancement. In the MLs, single QDs with featured exciton emissions are observed, whose time correlations prove single-photon emission with multi-photon probability

g^{(2)} (0) = 0.02

; some QDs show both biexciton

X X

and exciton X emissions and exhibit a perfect cascade feature. This work could pave a step towards a scalable array of QD single-photon sources and the application of QD photon-pair emission for entanglement experiments.

About Me

Prof. Haiqiao Ni is a researcher at the Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China. He completed his PhD studies at the National University of Singapore in 2002. He successfully developed room-temperature 1.0–1.6 micron GaInNAsSb/GaAs quantum well materials and was the first to report internationally the 1.55 micron GaInNAs/GaAs multi-quantum well resonance cavity enhancement detector (RCE-PD) and the 1.59 micron GaInNAsSb quantum well laser. His most recent research advances include the following: completion of the growth of a single-photon source based on InAs quantum dots; development of low-temperature GaAs materials for THz wave generation and detection; and the creation of an ultrashort pulsed semiconductor quantum dot laser integrated into a single chip. His research interests include near-infrared band semiconductor lasers and detectors; quantum dot single-photon sources; semiconductor ultrashort pulse lasers; THz wave generation and detection devices; silicon-substrate epitaxial growth of group III-V optoelectronic devices; and ultra-low-power light-emitting devices.

Ni Haiqiao

Ni Haiqiao

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