CHARGE-TRANSFER DYNAMICS OF ELECTROCHEMICAL DARK AND PHOTOPROCESSES ON SEMICONDUCTORS .1. MANIFOLD OF STATIONARITY CONDITIONS OF HYDROGEN REACTION EMERGING FROM DARK TO PHOTOREGIMES OF N-MATERIALS, AND DARK ADMITTANCE EVALUATION

The dynamics of electrochemical dark- and photoprocesses on semiconduc tors is governed by the sequence of electronic charge density transfer (partial charge transfer): prominent examples are two-step hydrogen r eactions. A case-study (valid for n-materials) of the dynamical manifo ld of stationarity conditions in the cathodic regime far from equilibr ium is presented for dark reaction under majority control and stepwise emerging minority rates under increased photoexcitation. From corresp onding admittance functions, the dark-admittance of hydrogen reaction is treated first. Numerical simulation based on stationary and photoad mittance data predicts dark-admittance patterns in accord with experim ent: Measurement of capacitive dark-admittance peak and of reactive lo ss factor prove a strong asymmetry of charge transfer sequence on n-Ga As, complementing photoadmittance evaluations covered in Part II.