ScholarBank@NUShttps://scholarbank.nus.edu.sgThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Sun, 24 Jan 2021 19:09:42 GMT2021-01-24T19:09:42Z50181- Shot noise characteristics of a resonant tunnelling diodehttps://scholarbank.nus.edu.sg/handle/10635/81159Title: Shot noise characteristics of a resonant tunnelling diode
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: The shot noise characteristics of a resonant tunnelling diode are calculated from the model which includes the effects of the effective transmission coefficient of electrons in the conduction band and in the subband of the accumulation layer in the emitter. The transit time is formulated for a double barrier structure. However, the transit time for electrons at the Fermi level and the subband of the emitter are different because of the energy difference. The results show that the shot noise spectrum is independent of the frequency at low and intermediate frequencies and dependent on the frequency at high frequencies.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/811591994-01-01T00:00:00Z
- Impact ionizing electroluminescence of a double barrier structurehttps://scholarbank.nus.edu.sg/handle/10635/80561Title: Impact ionizing electroluminescence of a double barrier structure
Authors: Sheng, H.; Chua, S.-J.
Abstract: The impact ionizing electroluminescence model of a unipolar double barrier structure has been developed. The electron density in the quantum well and the hole density generated in the collector region are based on electron current. The electroluminescence results from direct radiative recombination between the electrons and holes in the quantum well. The results show that a light on-off ratio of the electroluminescence can be obtained. © 1994 Chapman & Hall.
Tue, 01 Nov 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/805611994-11-01T00:00:00Z
- Properties of monolithic integration of a resonant tunneling diode and a quantum well laserhttps://scholarbank.nus.edu.sg/handle/10635/81025Title: Properties of monolithic integration of a resonant tunneling diode and a quantum well laser
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: An investigation of the electrical and optical characteristics of a resonant tunneling diode monolithically integrated with a quantum well laser is carried out. An analytic expression for the propagating model current is given in terms of the total spontaneous emission rate. The laser is pumped by the current emitted by the resonant tunneling diode. When the current in the laser exceeds the threshold current, laser light is produced. Since the current in the laser exhibits negative differential resistance similar in behavior to the current of a resonant tunneling diode, a bistable light output can be obtained from this new device.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/810251994-01-01T00:00:00Z
- Interface roughness effects on the currents of resonant tunnelling hot electron transistorhttps://scholarbank.nus.edu.sg/handle/10635/80620Title: Interface roughness effects on the currents of resonant tunnelling hot electron transistor
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: The effects of interface roughness on the resonant tunnelling hot electron transistor current are studied by calculating an average effective transmission coefficient for the quantum well structure. Our model for the transmission coefficient includes both quantum interference and bulk scattering. The interface roughness is represented by a rectangular distribution having the width of one atomic layer. The results indicate that the interface roughness will lower and broaden the resonant peak. The emitter peak tunnelling current, base current and collector current will be reduced by 50% at room temperature. The effect of interface roughness on the gain is relatively weak.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/806201994-01-01T00:00:00Z
- Modelling of a resonant tunnelling hot electron transistorhttps://scholarbank.nus.edu.sg/handle/10635/62430Title: Modelling of a resonant tunnelling hot electron transistor
Authors: Sheng, H.; Chua, S.-J.
Abstract: A semiclassical model of a resonant tunnelling hot electron transistor (RHET) is proposed. The model includes quantum interference and multiple scattering by means of a correlation function and mean free path. The DC properties of a RHET are calculated and analysed. The results show that the maximum common-emitter current gain of a RHET can be achieved by modulating the base width and barrier height of the emitter resonant tunnelling structure.
Fri, 01 Jan 1993 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/624301993-01-01T00:00:00Z
- Electroluminescence model of bipolar resonant tunnelling diodehttps://scholarbank.nus.edu.sg/handle/10635/62115Title: Electroluminescence model of bipolar resonant tunnelling diode
Authors: Sheng, H.; Chua, S.-J.
Abstract: An electroluminescence model of a bipolar resonant tunnelling diode is carried out. The current is the sum of the electron and hole current. The electron and hole density at the resonant level of a quantum well are related to the electron and hole current, respectively. A radiative recombination rate formula is derived from the matrix element, electron and hole distribution. The results show that a large on-off ratio of light output can be achieved by the bipolar resonant tunnelling diode. © 1994 Chapman & Hall.
Fri, 01 Apr 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/621151994-04-01T00:00:00Z
- Proposing and modelling of a new unipolar transistorhttps://scholarbank.nus.edu.sg/handle/10635/62660Title: Proposing and modelling of a new unipolar transistor
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: A new unipolar transistor has been proposed. Modelling was carried out using a semiclassical transport theory, which included quantum interference and multiple scattering by means of a correlation function and taking account of the mean free path. The direct current properties of the new transistor are calculated and analyzed. The results show that a common-emitter current gain of 80 can be expected.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/626601994-01-01T00:00:00Z
- Enhancement of electroluminescence properties in delta-doped quantum well of bipolar resonant tunneling diodehttps://scholarbank.nus.edu.sg/handle/10635/62139Title: Enhancement of electroluminescence properties in delta-doped quantum well of bipolar resonant tunneling diode
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: An analytical model of δ-doped quantum well is developed. The results show that by using δ-doped quantum well structure, the area densities of the electrons and holes in the conduction and valence bands respectively can be increased by 4 orders of magnitudes compared with the n-i-p structure. Therefore the electroluminescence enhancement can be expected for the bipolar resonant tunneling diode of δ-doped quantum well.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/621391994-01-01T00:00:00Z
- Electroluminescence properties of bipolar resonant tunneling diodehttps://scholarbank.nus.edu.sg/handle/10635/62116Title: Electroluminescence properties of bipolar resonant tunneling diode
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: An electroluminescence model of bipolar resonant tunneling diode is carried out. The current is the sum of electron and hole current. The electron and hole density at resonant level of quantum well are related with the electron and hole current respectively. Radiative recombination rate formula is derived from matrix element, electrons and holes distribution. Result shows the large on-off ratio of light output can be achieved by the bipolar resonant tunneling diode.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/621161994-01-01T00:00:00Z
- New hole negative differential resistance strained-layer devicehttps://scholarbank.nus.edu.sg/handle/10635/62478Title: New hole negative differential resistance strained-layer device
Authors: Sheng, H.; Chua, S.-J.
Abstract: A new negative differential resistance device making use of hole transport was developed and studied theoretically. The device consists of an InGaAs strained-layer quantum well, an AlGaAs barrier and a GaAs quantum well. The real space transfer phenomenon occurs in the GaAs and InGaAs quantum wells. For heterolayer transport, the distribution function which is calculated from the wavefunction of the hole can be used to describe the transport phenomena of the particles. The current of the device is controlled by the distribution function. The peak-to-valley current ratio is determined by the ratio of the effective masses of holes in the normal and strained quantum wells and the hole transmission coefficient. © 1995.
Fri, 01 Dec 1995 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/624781995-12-01T00:00:00Z
- Properties of monolithic integration of a resonant tunneling diode and a quantum well laserhttps://scholarbank.nus.edu.sg/handle/10635/62658Title: Properties of monolithic integration of a resonant tunneling diode and a quantum well laser
Authors: Sheng, H.; Chun, S.-J.
Abstract: An investigation of the electrical and optical characteristics of a resonant tunneling diode monolithically integrated with a quantum well laser is carried out. An analytic expression for the propagating model current is given in terms of the total spontaneous emission rate. The laser is pumped by the current emitted by the resonant tunneling diode. When the current in the laser exceeds the threshold current, laser light is produced. Since the current in the laser exhibits negative differential resistance similar in behavior to the current of a resonant tunneling diode, a bistable light output can be obtained from this new device. © 1994 Academic Press. All rights reserved.
Thu, 01 Sep 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/626581994-09-01T00:00:00Z
- Proposing and modelling of a new unipolar transistorhttps://scholarbank.nus.edu.sg/handle/10635/81027Title: Proposing and modelling of a new unipolar transistor
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: A new unipolar transistor has been proposed. Modelling was carried out using a semiclassical transport theory, which included quantum interference and multiple scattering by means of a correlation function and taking account of the mean free path. The direct current properties of the new transistor are calculated and analyzed. The results show that a common-emitter current gain of 80 can be expected.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/810271994-01-01T00:00:00Z
- Subband current in resonant tunneling diodehttps://scholarbank.nus.edu.sg/handle/10635/62826Title: Subband current in resonant tunneling diode
Authors: Sheng, H.; Sinkkonen, J.
Abstract: An accumulation layer is formed on the emitter side of a biased resonant tunneling diode (RTD) leading to a similar subband structure as in the ordinary MOS-system. Electrons occupying the subbands can tunnel through the RTD-structure and give rise to a significant contribution to the diode current. We calculate the subband current from our semiclassical transport model developed earlier for the ordinary tunneling current. The model includes quantum interference and bulk scattering by utilizing an optical approximation for the coherent part of the wave function. The subband current turns out to be of the same order of magnitude as the ordinary tunneling current component. It is shifted to higher voltages and therefore it increases the valley current. In order to reduce the subband current and improve the peak-to-valley current ratio (PVCR), we propose a novel RTD-structure with a grading in front of the emitter barrier. The purpose of the grading is to suppress the formation of the accumulation layer and thereby decrease the valley current. Calculations show that PVCR increases by a factor of two using a proper design of the grading. © 1992.
Wed, 01 Jan 1992 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/628261992-01-01T00:00:00Z
- Shot noise characteristics of a resonant tunnelling diodehttps://scholarbank.nus.edu.sg/handle/10635/62761Title: Shot noise characteristics of a resonant tunnelling diode
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: The shot noise characteristics of a resonant tunnelling diode are calculated from the model which includes the effects of the effective transmission coefficient of electrons in the conduction band and in the subband of the accumulation layer in the emitter. The transit time is formulated for a double barrier structure. However, the transit time for electrons at the Fermi level and the subband of the emitter are different because of the energy difference. The results show that the shot noise spectrum is independent of the frequency at low and intermediate frequencies and dependent on the frequency at high frequencies.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/627611994-01-01T00:00:00Z
- Modelling of a resonant tunnelling hot electron transistorhttps://scholarbank.nus.edu.sg/handle/10635/80743Title: Modelling of a resonant tunnelling hot electron transistor
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: A semiclassical model of a resonant tunnelling hot electron transistor (RHET) is proposed. The model includes quantum interference and multiple scattering by means of a correlation function and mean free path. The DC properties of a RHET are calculated and analyzed. The results show that the maximum common-emitter current gain of a RHET can be achieved by modulating the base width and barrier height of the emitter resonant tunnelling structure.
Sun, 01 Aug 1993 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/807431993-08-01T00:00:00Z
- New hole negative differential resistance strained-layer devicehttps://scholarbank.nus.edu.sg/handle/10635/80804Title: New hole negative differential resistance strained-layer device
Authors: Sheng, H.; Chua, S.-J.
Abstract: A new negative differential resistance device making use of hole transport was developed and studied theoretically. The device consists of an InGaAs strained-layer quantum well, an AlGaAs barrier and a GaAs quantum well. The real space transfer phenomenon occurs in the GaAs and InGaAs quantum wells. For heterolayer transport, the distribution function which is calculated from the wavefunction of the hole can be used to describe the transport phenomena of the particles. The current of the device is controlled by the distribution function. The peak-to-valley current ratio is determined by the ratio of the effective masses of holes in the normal and strained quantum wells and the hole transmission coefficient. © 1995.
Fri, 01 Dec 1995 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/808041995-12-01T00:00:00Z
- Impact ionizing electroluminescence of a double barrier structurehttps://scholarbank.nus.edu.sg/handle/10635/62304Title: Impact ionizing electroluminescence of a double barrier structure
Authors: Sheng, H.; Chua, S.-J.
Abstract: The impact ionizing electroluminescence model of a unipolar double barrier structure has been developed. The electron density in the quantum well and the hole density generated in the collector region are based on electron current. The electroluminescence results from direct radiative recombination between the electrons and holes in the quantum well. The results show that a light on-off ratio of the electroluminescence can be obtained. © 1994 Chapman & Hall.
Tue, 01 Nov 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/623041994-11-01T00:00:00Z
- Interface roughness effects on the currents of resonant tunnelling hot electron transistorhttps://scholarbank.nus.edu.sg/handle/10635/62346Title: Interface roughness effects on the currents of resonant tunnelling hot electron transistor
Authors: Sheng, Hanyu; Chua, Soo-Jin
Abstract: The effects of interface roughness on the resonant tunnelling hot electron transistor current are studied by calculating an average effective transmission coefficient for the quantum well structure. Our model for the transmission coefficient includes both quantum interference and bulk scattering. The interface roughness is represented by a rectangular distribution having the width of one atomic layer. The results indicate that the interface roughness will lower and broaden the resonant peak. The emitter peak tunnelling current, base current and collector current will be reduced by 50% at room temperature. The effect of interface roughness on the gain is relatively weak.
Sat, 01 Jan 1994 00:00:00 GMThttps://scholarbank.nus.edu.sg/handle/10635/623461994-01-01T00:00:00Z