Photon-assisted breakdown, negative resistance, and switching in a quantum-well transistor laser

Abstract

Data are presented on the transistor laser with collector bias and photon-assisted tunneling causing, under the constraints IE+IB+IC=0 (α=ΔIC∕ΔIE) and α→1, breakdown and negative resistance effects in the IC-VCE characteristics. Collector bias, aided by photon-assisted tunneling (Franz—Keldysh absorption), supplies holes to the n-p-n transistor base by tunneling escape of electrons (ΔIB=0), “feeding” quantum-well recombination radiation (generation and regeneration, ΔIE=ΔIC=ΔIhv) and yielding the negative resistance/switching condition α→1 (α=ΔIC∕ΔIE, ΔIC=ΔIE, ΔIB=0, IE+IB+IC=0), and, as a consequence, corners, negative resistance, switching, vertical collector current (ΔVCE≈0), spectral change, and mode hopping effects in the IC-VCE characteristics.

Performance Optimization of GaAs-Based Vertical-Cavity Surface-Emitting Transistor-Lasers

“…A similar breakdown in I C has previously been observed on npn-type T-VCSELs by Wu et al [2,4], who attributed it to a photon reabsorption process (Franz-Keldysh effect) in the base-collector junction that adds carriers to I C and also acts as a source of resupply of majority carriers to the base [4,9]. However, Franz-Keldysh absorption would here not be expected to increase beyond the breakdown in I C (at I B =I B,BD ) since any further increase in I B (corresponding to an increase in V EB and thereby a decrease in V BC =V EC -V EB ) will decrease rather than increase the band bending in the base-collector junction.…”

Analysis of Tunable Internal Loss Caused by Franz–Keldysh Absorption in Transistor Lasers

“…As a result, the accumulated carriers there impede the successive photon absorption because of the Pauli exclusion principle. The phenomenon of saturation in α FK may be modeled as α FK (N p , E) = α FK0 (E) 1 + ε FK N p (5) where N p is the photon density, ε FK is an absorption suppression coefficient for the FK absorption, and E is the electrical field applied to the junction. The calculations of L-I and L-IV curves with ε FK = 3 × 10 −15 cm −3 are presented in Figs.…”

“…With quantum wells (QWs) incorporated into the base regions of heterojunction bipolar transistors and with an improved optical confinement in the active regions, the buildup of the photon number and therefore lasing condition are achievable. The TL invented by Feng and Holonyak Jr. in 2004 demonstrated superiority in various functionalities such as the capability of nonlinear mixing [2], frequency multiplication [3], [4], negative resistance [5], photon-assisted switching [6], resonance-free operation with a modulation bandwidth of 20 GHz [7], and simultaneous electrical and optical open-eye signals at a 40 Gb/s data rate [8]. Previous results of the TL mainly focused on the unique current-voltage (I-V) and light-versus-current-voltage (L-IV) characteristics and high-speed performance.…”

Investigation of effective base transit time and current gain modulation of light-emitting transistors under different ambient temperatures

“…These layers are followed by a 557 Å n-type subcollector layer, a 120 Å In 0.49 Ga 0.51 P etch stop layer, and a 2871 Å undoped GaAs collector layer. The active layer design consists of a 1358 Å average p-doped 3 Â 10 19 is completed with the growth of a 511 Å n-type In 0.49 Ga 0.51 P wide-gap emitter layer, the upper cladding layers (the same as the bottom ones), and a 2000 Å heavily doped n-type GaAs contact layer. The HBT structure is identical to the LET structure except for the insertion of two QWs in the base region.…”

“…When V CE increases from 1.5 to 2.5 V at constant base current I B , the conventional HBT shows a decrease of the collector current (I C ), i.e., current gain drops, which is usually seen due to high power dissipation. However, the LET exhibits the reverse trend due to the photon-assisted tunneling (Franz-Keldysh absorption), 19 where the photongenerated holes are re-supplied to the base region while electrons are injected to the collector region, causing I C increases with V CE .…”