Sangmoon Han

Sangmoon Han
Washington University in St. Louis | WUSTL , Wash U · Department of Mechanical Engineering and Materials Science

Doctor of Engineering

About

19
Publications
1,364
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
109
Citations
Citations since 2017
19 Research Items
109 Citations
2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040
Introduction
Two-dimensional materials based layer transfer (2DLT)/ Material growth/ Nanomembrane/ Wearable inorganic electronics/ Solar energy harvesting

Publications

Publications (19)
Article
Full-text available
Epitaxy of single-crystalline materials laid the foundation for numerous electronics as a core technology. Nevertheless, because the single-crystalline epilayers are covalently bonded to substrates, only limited applications were explored. The recent development of layer transfer techniques has suggested another way involving the production of free...
Article
We successfully develop a self-powered image array (IA) composed of 16 touch-free sensors (TFSs) fabricated with semiconductor InN nanowires (NWs) as a response medium. Without using a power supply, the InN-NW TFS can detect the position of a human hand 30 cm away from the device surface. It also distinguishes different materials such as polyimide,...
Article
We report the first demonstration of flexible photodetectors, operating at the wavelength window of 1.3 μm, fabricated with InN nanowires (NWs) and graphene on an overhead projector transparency (OHP) sheet. The InN NWs, used as an absorption medium for the device, were formed on a Si substrate and exhibited strong emission with a peak wavelength o...
Article
We report improved photoelectrochemical water splitting (PEC-WS) using GaN nanowires (NWs) with reverse-mesa structures (RMNWs) formed on Si(111) as a photoanode material. The GaN-RMNW photoanode exhibited a current density of 2.62 mA/cm2 and an applied photonto- current efficiency of 1.65% at 0.6 V versus a reversible hydrogen electrode. These val...
Article
The performance of photoelectrochemical water splitting (PEC-WS) over time was drastically improved using new carrier-guiding semiconductor nanostructures, namely InGaN/GaN core-shell nanowires (CSNWs) with a protruding core, as a photocathode (PC) material. The InGaN/GaN CSNWs designed in this study enable photo-generated electrons to accumulate a...
Article
We report the high solar-to-hydrogen conversion efficiency (STH) and long-term stability of a photoelectrochemical water-splitting (PEC-WS) system using GaN pyramidal dots (PDs) coated with oxidized tungsten sulfide (OTS) as the...
Article
We report the successful demonstration of a light-assisted NO2gas sensor that operates at room temperature with high response. The gas sensor was fabricated with high-crystalline undoped-GaN nanowires (NWs) and graphene functioning as the light-absorbing medium and carrier channel, respectively. Exposure of the gas sensor to the NO2concentration of...
Conference Paper
In this paper, we report the improvement of photoelectrochemical water splitting (PEC-WS) performance using InGaN/GaN hetero-structure nanowires (HSNWs) as a photocathode. The InGaN/GaN HSNWs are schematically described in Figure 1a. GaN nanowires (NWs) with the height of 109 nm were first formed on a Si(111) substrate as nucleation sites. And then...
Article
We report an approach to improve the photoelectrochemical water splitting (PEC-WS) performance using GaN-nanowire (NW) bundles (GNW-BDLs) as the photoanode material. The bundles were formed by dipping GaN NWs with...
Article
In the present study, we have achieved high-performance photoelectrochemical water splitting (PEC-WS) using GaN nanowires (NWs) coated with tungsten sulfide (W x S1-x) (GaN-NW-W x S1-x) as a photoanode. The measured current density and applied-bias photon-to-current efficiency were 20.38 mA/cm2 and 13.76%, respectively. These values were much highe...
Article
We discuss the formation mechanism of GaN nanowires (NWs) with various shapes grown on Si(111) by using a plasma-assisted molecular-beam epitaxy. The GaN NWs have not only symmetrical structures but also various features such as reverse-mesa and reverse-funnel shapes. To manipulate the shape of GaN NWs, we controlled the growth kinetics of gallium...
Conference Paper
We discuss the growth mechanism of GaN nanowires (NWs) with various shapes formed on Si(111) by a plasma-assisted molecular beam epitaxy. To investigate the growth mechanism of the GaN NWs, the growth kinetics of Ga-atoms were controlled by varying V/III ratio, defined as the ratio of N flux to Ga flux, growth temperature, and formation rate. In fi...
Article
We report the fast response characteristics of flexible ultraviolet (UV) photosensors with GaN nanowires (NWs) and a graphene channel. The GaN NWs used as light-absorbing media are horizontally and randomly embedded in a graphene sandwich structure in which the number of bottom graphene layers is varied from zero to three and the top is a fixed sin...
Article
The development of epidermal electronics, which provides precise measurement of various human physiological signals without reducing the quality of life, has encountered a serious delay in its practical application because of potential damage experienced during fabrication. Such damage occurs mainly because fabrication of the epidermal device is ty...
Article
Full-text available
In this study, we report highly efficient and flexible photosensors with GaN nanowires (NWs) horizontally embedded in a graphene sandwich structure fabricated on polyethylene terephthalate (PET). GaN NWs and the graphene sandwich structure are used as light-absorbing media and the channel for carrier movement, respectively. To form uniform high-qua...
Article
Full-text available
We report on the dependence of internal crystal structures on the electrical properties of a catalyst-free and undoped InAs nanowire (NW) formed on a Si(111) substrate by metal–organic chemical vapor deposition. Cross-sectional transmission electron microscopy images, obtained from four different positions of a single InAs NW, indicated that the wu...

Network

Cited By