p–n junction

About: p–n junction is a research topic. Over the lifetime, 7701 publications have been published within this topic receiving 108890 citations. The topic is also known as: p-n junction.

Pnp GaAs/Ge/Ge phototransistor grown by molecular beam epitaxy: Implications for bipolar and hot‐electron transistors

Abstract: In order to exploit the potential of GaAs/Ge heterojunctions for high‐speed heterojunction bipolar transistors and hot‐electron transistors, a Pnp GaAs/Ge floating base phototransistor, sensitive to 1.1–1.55‐μm wavelength range, was made. The gallium‐doped Ge substrate was first exposed to the As2 flux in the growth chamber of a molecular beam epitaxy system to form a pn junction in Ge. This was followed by the growth of a p‐type Be‐doped GaAs layer which served as the emitter. The fabricated mesa devices showed an optical gain of 85 at 1.15 μm incident wavelength. The gain was found to be nearly independent of the incident light power indicating good quality of the GaAs/Ge heterointerface.

Selective p- and n-Doping of Colloidal PbSe Nanowires To Construct Electronic and Optoelectronic Devices.

Abstract: We report the controlled and selective doping of colloidal PbSe nanowire arrays to define pn junctions for electronic and optoelectronic applications. The nanowires are remotely doped through their surface, p-type by exposure to oxygen and n-type by introducing a stoichiometric imbalance in favor of excess lead. By employing a patternable poly(methyl)methacrylate blocking layer, we define pn junctions in the nanowires along their length. We demonstrate integrated complementary metal-oxide semiconductor inverters in axially doped nanowires that have gains of 15 and a near full signal swing. We also show that these pn junction PbSe nanowire arrays form fast switching photodiodes with photocurrents that can be optimized in a gated-diode structure. Doping of the colloidal nanowires is compatible with device fabrication on flexible plastic substrates, promising a low-cost, solution-based route to high-performance nanowire devices.

Computational simulation of the p‐n doped silicon quantum dot

Abstract: Elongated crystalline silicon quantum dot (QD) codoped with aluminum and phosphorous together has been modeled with a formula of Si36Al1P1H42. The calculations of electronic structure are done by VASP software in the basis of plane waves, and valent electrons are treated explicitly while core electrons are described with pseudopotentials. Compared with undoped model, Si38H42, the results show the features in the electronic structure of the codoped QD of lowest unoccupied molecular orbital and highest occupied molecular orbital contributed by dopants, and transitions between those bands make contributions to many properties different from undoped model. The role of thermal motion of ions was also explored at (i) high and (ii) ambient temperatures. (i) At high temperature, the thermal motion of ions leads to the break of crystal structure. (ii) At ambient temperatures, the motion of ions facilitates the nonadiabatic couplings between electronic states. The relevant electronic dynamics also calculated with computed nonadiabatic couplings. This simulation predicts the charge transfer across p-n junction on atomistic scale. © 2012 Wiley Periodicals, Inc.

Interpretation of current flow in photodiode structures using laser beam-induced current for characterization and diagnostics

Abstract: This paper presents an interpretation of the physical mechanisms involved in the generation of laser beam-induced current (LBIC) in semiconductor p-n junction diodes. LBIC is a nondestructive semiconductor characterization technique that has been used in a qualitative manner for a number of years and is especially useful for examining individual photodiodes within large two-dimensional arrays of devices. The main thrust of this work is the analysis of LBIC in terms of nonzero steady-state circulatory current flow within the device and, hence, the interpretation of LBIC line profiles to diagnose the patterns of current flow within the structure. This provides an important basis for future studies seeking to relate LBIC to indicators of p-n junction performance and integrity such as dark current components and reverse bias saturation current. In particular, this paper examines the ideal cases of a single isolated p-n junction diode structure, and also considers an array of such devices in close proximity to each other. Modifications to the idealized theory that are required to account for localized junction leakage and surface recombination are presented, and the effect of Schottky contacts is discussed. Numerical simulations based on the HgCdTe family of semiconductors are presented to support the theory.

Interband tunneling in heterostructure tunnel diodes

Abstract: A particular type of tunnel diode, incorporating a wideband tunnel barrier, is studied. Simple analytic expressions are developed for estimating the tunneling coefficients to guide and optimize the design of heterostructure interband tunnel devices. The interband tunneling in such heterostructure tunnel diodes is modeled by a two-band Schrodinger equation. For a certain family of InGaAs/InA/GaAs p-n junction tunnel diodes, the interband transmission coefficients are calculated. The estimated peak currents are shown to compare very favorably with experimental results. >