Theory and experiments on open circuit voltage decay of p-n junction diodes with arbitrary base width, including the effects of built-in drift field in the base and recombinations in the emitter

Abstract

An expression for the forward current induced open circuit voltage decay of a p-n junction diode with a finite base width is derived. The expression includes the effects of recombination in the emitter and the built-in drift field in the base which may arise due to a nonuniform impurity profile. The voltage decay rate is dependent on the base thickness, base drift field, emitter dark saturation current, the effective surface recombination velocity at the back contact, and the minority carrier lifetime in the base. The effects of the drift field in the emitter, emitter lifetime, and surface recombination velocity at the emitter surface are completely taken into account by the emitter saturation current. Experimentally observed voltage decay plots for thin base hyperabrupt varactor diodes with retrograded impurity gradients in the base are reported. It is shown that the experimental results can be interpreted satisfactorily using the above theory. The values of the minority-carrier lifetime in the base are determined from the experimental results.

Measurement of Base Lifetime and Effective Back Surface Recombination Velocity in BSF Solar Cells

“…The asymptotic decay times of short-circuit cunent and opencircuit voltage given by eqns (5a) and (4a) can be combined to yield the following equation, (7) where t1 and tz are given by eqns (4b) and (5b) respecti\ely. The right hand side (RHS) of eqn (7) is independent of 'tB and is a function of w 8 , Serf and JEo· If JEo is known, the RHS becomes only a function of Serf for a cell of known thickness w 8 and hence Serf can be determined in principle from the measured values of (Terr)c and ('\'err>v· Once the value of Seff is known, Ts can be easily determined from eqn (4a) or eqn (5a).…”

“…The expression for the voltage decay for a diode with any arbitrary base thickness was recently derived including the recombinations in the emitter (7,8) and is given by …”

Effective Lifetime Experimental Measurement under External Magnetic Field in Transient Dynamic State Obtained from a Square Electrical Excitation by Open Circuit Voltage Decay Method

“…In practice, this technic tends to be subjective and unreliable because the difficulty frequently arises in finding a region of the decay which reasonably linear. However, there are been recent developments in both experimental [4] and theoretical [5] areas which are significantly improved the reliability and accuracy of the approach. In this method, a voltage is induced in the solar cell and is then allowed to decay under open circuit conditions.…”

Voctransient in silicon heterojunction solar cells withµc-SiOx:H window layers

“…In addition, the investigation into the rising edge of the V oc transient curve, to our knowledge, has not been reported [31,32]. The theoretical studies of V oc transients have mainly been based on the continuity equation which was solved using the boundary conditions and quasi-static approximation [33]. Researchers often neglect the term of the electric field in the continuity equation for save computational time [26,27,33] except for [33].…”

“…The theoretical studies of V oc transients have mainly been based on the continuity equation which was solved using the boundary conditions and quasi-static approximation [33]. Researchers often neglect the term of the electric field in the continuity equation for save computational time [26,27,33] except for [33]. So the effect of the electric field on diode solar cell performance has not often been worked out by V oc transient measurement.…”