وبسایت مهندسی الکترونیک و کامپیوتر

این پژوهش یک مرور کلی از سلول های خورشیدی و سلول های خورشیدی چند پیوندی را بیان می کند. بخش اول این نوشتار فیزیک پایه و طراحی سلول های خورشیدی تک پیوندی را توصیف می کند. همچنین تاریخچه سلول های خورشیدی و مزایای استفاده از فناوری خورشیدی شرح داده می شوند. بخش دوم این مقاله فیزیک، طراحی و فرایند ساخت سلول های خورشیدی مولتی جانکشن را تشریح می کند. در این بخش روی توضیحات تمرکز شده و برخی از مشکلات بالقوه سلول های خورشیدی مولتی جانکشن توصیف می شوند. در بخش پایانی مقاله استفاده عملی از سلول های خورشیدی مولتی جانکشن و چشم انداز آن برای پیشرفت طراحی های آینده بحث می شود. در این بخش در مورد اینکه سلول های خورشیدی مولتی جانکشن که در حال حاضر وجود دارند و پیشرفت های ممکن آینده آنها بحث می شود. 
 

In this paper, we propose and evaluate a novel design of a lightly doped drain and source carbon nanotube field effect transistor (LDDS-CNTFET) with a negative differential resistance (NDR) characteristic, called negative differential resistance LDDS-CNTFET (NDR-LDDS-CNTFET). The device was simulated by using a non equilibrium Green’s function method. To achieve this phenomenon, we have created two quantum wells in the intrinsic channel by using two n-type regions. In the wells that are separated by a thin barrier, two resonance states are generated. On the other hand, the thickness of the barrier between the source and the well is variable depending on the energy level. Accordingly, with increasing gate-source voltage, the number of tunneling electrons and consequently drain-source current are varied. Furthermore, we have presented a structure with two n-type and three p-type regions in the channel that illustrates a larger NDR region. In this structure, the peak and valley of the drain-source current are shifted when compared with the previous structure. Finally, we investigated the effect of doping concentration on the NDR parameter.

Abstract - The effects of doping on the performance of coaxially gated carbon nanotube (CNT) field-effect transistors for both zero Schottky-barrier (SB) and doped carbon nanotube contacts are theoretically investigated. For ultrascaled CNTFETs in which the source/drain metal contacts lie 50 nm apart, there is no MOSFET-like contact CNTFET (C-CNTFET) with an acceptable on/off current ratio using a CNT of diameter >= 1.5 nm and a source/drain voltage >= 0.4 V. For CNTFETs with source/drain metal contacts either 50 nm or 100 nm apart, there is an optimal doping concentration of 1e-3 dopants per atom. The maximum on/off current ratios for the 50 nm CNT/5 nm gate and the 100 nm CNT/10 nm gate SB-CNTFETs are 5e4 and 6e5, respectively. Performance metrics of delay time, cutoff frequency, and LC frequency are presented and compared.

Abstract - New integrated optical devices combining an InGaAsP/InP HPT and an inner-stripe LED are proposed and their fabrication processes are described. The device functions of light amplification, optical bistability, and optical switching are demonstrated in the 1-um wavelength region.

I. INTRODUCTION: MONOLITHIC integration of well-developed discrete devices such as lasers, light-emitting diodes (LED’s), phototransistors, p-i-n diodes, and avalanche photodiodes (APD’s) has been drawing much attention for better performance and higher reliability [ 11, [2]. By integration, on the other hand, new functions which cannot be expected for the discrete optoelectronic devices can be realized utilizing the optical or electrical interactions between two or more optoelectronic devices [3]-[ ll].

Abstract - We perform the numerical analysis of a CIGS solar cell parameters such as open circuit voltage, short circuit current, maximum power, fill factor, and external quantum efficiency as a function of absorber layer band gap. These parameters are known to be the key parameters of a solar cell to determine its performance. We change the band gap of the CIGS absorber layer by changing its alloy composition. ATLAS SILVACO is used to construct and simulate the CIGS solar cell structure with standard AM1.5 spectra. The open circuit voltage and the maximum power increase almost linearly with the band gap. However, the change in short circuit current and the fill factor with the CIGS bandgap does not show any formal relation. We found that the change in fill factor due to the band gap change is not significant compared to the change in open circuit voltage.