Entity

Time filter

Source Type


Li Z.,CAS Institute of Semiconductors | Xiao H.,CAS Institute of Semiconductors | Wang X.,CAS Institute of Semiconductors | Wang X.,ISCAS XJTU Joint Laboratory of Functional Materials and Devices for Informatics | And 5 more authors.
Physica B: Condensed Matter | Year: 2013

In this study, potential efficiency of InGaN/Si mechanically stacked two-junction solar cell is theoretically investigated by optimizing the band gap and thickness of the top InGaN cell. Results show that the optimum conversion efficiency is 35.2% under AM 1.5 G spectral illuminations, with the bandgap and thickness of top InGaN solar cell are 2.0 eV and 600 nm, respectively. The results and discussion would be helpful in designing and fabricating high efficiency InGaN/Si mechanically stacked solar cell in experiment. © 2013 Elsevier B.V. All rights reserved. Source


Ding J.,CAS Institute of Semiconductors | Wang X.,CAS Institute of Semiconductors | Wang X.,ISCAS XJTU Joint Laboratory of Functional Materials and Devices for Informatics | Xiao H.,CAS Institute of Semiconductors | And 5 more authors.
Journal of Alloys and Compounds | Year: 2012

We present calculations of carrier confinement characteristics in (Al yGa 1-yN/AlN)SLs/GaN/(In xGa 1-xN/GaN) MQW/GaN heterojunction structure in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations were made using a self-consistent solution of the Schrödinger, Poisson, potential and charge balance equations. An optimization of In xGa 1-xN/GaN multiquantum-well (MQW) was made firstly including thickness of GaN channel, InGaN, and indium composition of In xGa 1-xN in order to increase carrier density and mobility, and the influence of pairs of AlGaN/AlN superlattices (SLs) and InGaN/GaN MQWs on structure was discussed. Theoretical calculations clearly indicate that the two-dimensional electron gas (2DEG) sheet carrier density in designed heterostructure is greatly increased due to the enhancing of carrier confinement compared to those in conventional AlGaN/GaN one at the similar Al composition. Furthermore, the calculated carrier distribution shows that carrier mobility will be improved by reducing interface roughness and alloy disorder scattering in designed heterostructure. © 2012 Elsevier B.V. Source


Ding J.,CAS Institute of Semiconductors | Wang X.,CAS Institute of Semiconductors | Wang X.,ISCAS XJTU Joint Laboratory of Functional Materials and Devices for Informatics | Xiao H.,CAS Institute of Semiconductors | And 5 more authors.
Physica B: Condensed Matter | Year: 2012

We present numerical optimization of carrier confinement characteristics in (Al xGa 1-xN/AlN)SLs/GaN heterostructures in the presence of spontaneous and piezoelectrically induced polarization effects. The calculations were made using a self-consistent solution of the Schrödinger, Poisson, potential and charge balance equations. It is found that the sheet carrier density in GaN channel increases nearly linearly with the thickness of AlN although the whole thickness and equivalent Al composition of Al xGa 1-xN/AlN superlattices (SLs) barrier are kept constant. This result leads to the carrier confinement capability approaches saturation with thicknesses of AlN greater than 0.6 nm. Furthermore, the influence of carrier concentration distribution on carrier mobility was discussed. Theoretical calculations indicate that the achievement of high sheet carrier density is a trade-off with mobility. © 2012 Elsevier B.V. All rights reserved. Source


Wan X.-J.,CAS Institute of Semiconductors | Wang X.-L.,CAS Institute of Semiconductors | Wang X.-L.,ISCAS XJTU Joint Laboratory of Functional Materials and Devices for Informatics | Wang X.-L.,Xian Jiaotong University | And 9 more authors.
Chinese Physics Letters | Year: 2013

The valence band offset (VBO) of an Al0.17Ga0.83N/GaN heterojunction is determined to be 0.13 ± 0.07 eV by x-ray photoelectron spectroscopy. From the obtained VBO value, the conduction band offset (CBO) of ∼0.22 eV is obtained. The results indicate that the Al0.17Ga0.83N/GaN heterojunction exhibits a type-I band alignment. © 2013 Chinese Physical Society and IOP Publishing Ltd. Source


Li W.,CAS Institute of Semiconductors | Wang X.,CAS Institute of Semiconductors | Wang X.,Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices | Wang X.,ISCAS XJTU Joint Laboratory of Functional Materials and Devices for Informatics | And 7 more authors.
Journal of Alloys and Compounds | Year: 2014

The high electron mobility transistor (HEMT) structure employing novel InxAl1-xN/AlN multiple-quantum-wells (MQWs) as barrier layer is presented. The two-dimensional electron gas (2DEG) characteristics of (InxAl1-xN/AlN) MQWs/GaN heterojunction have been investigated by solving coupled Schrödinger and Poisson equations self-consistently. The influence of AlN thickness, InxAl1-xN thickness, In content and pair number of (InxAl1- xN/AlN)MQWs on sheet carrier density is investigated. AlN thickness dependence of carriers in barrier layer to total carriers in HEMT and In 0.18Al0.82N conduction band diagrams are discussed. The sheet carrier density of (In0.18Al0.82N/AlN)MQWs/GaN heterojunction is larger than that of (AlxGa1 -xN/GaN)SLs/GaN heterojunction and achieves to as large as 3.59 × 1013 cm-2 with AlN thickness of 1.4 nm, barrier thickness of 15 nm and pair number of 5. The calculation shows that (In0.18Al0.82N/AlN)MQWs provide high barrier which confines the 2DEG effectively. © 2014 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations