The bistability effect in a bipolar transistor with resonant-tunnelling collector structure

Abstract

A bipolar transistor incorporating a resonant-tunnelling structure in its collector is investigated using both analytical a n d ensemble Monte Carlo particle models. A resonant-tunnelling transistor of t h i s type has two current states for a certain range of collector-base voltage. The double-valued characteristics and bistability effect are connected with electron space charge in t h e collector region

Heterostructure laser-transistors controlled by resonant-tunnelling electron extraction

“…The mobile electron space-charge accumulated in the collector n-layer (behind the RTS) when the RTS is open affects the electric field in the RTS. This creates a feedback [5,7] which can lead to the electric bistability of the LT and in turn to bistable light-voltage dependences. The electron heating in the QWAR adds complexity to the LT operation and, in particular, to its controllability.…”

“…It is natural to assume that the electrons in the continuum states of the QWAR form a nondegenerate electron gas. In this case expressions (7) and ( 8), taking into account (6), can be rewritten as…”

“…It is seen from relationships ( 7)-( 10) that to a good approximation j CS = 0 only if ε RT ≥ ε i and j QW = 0 if ε RT 0. The energy of the RT level can be given by the following equation [5,7]:…”

“…The term with ρ C can reflect also the effect of the charge inside the RTS, though in the LT structure under consideration the latter is much smaller than the mobile electron charge en C . This term is responsible for the bistable behaviour of electric characteristics [7] and for the light-voltage characteristics [5] which are the subject of our study.…”

“…If the width of the RT level is small or the effective resistance ρ C and the collector current density are large, the mobile electron charge in the collector n-layer can markedly influence the RT level position (see equation (11)). This leads to the bistable behaviour of the collector current [7]. Taking into consideration this effect and using equations ( 11), ( 16), (18) and (19) we obtain the following equations for the collector current density (instead of equations (22) and ( 24)):…”