G. Zanarini

Plasma Time in Semiconductor Detectors

Several experimental results are given on plasma time in solid state detectors. They were obtained by various kinds of ionizing particles (?-particles, deuterons and protons) incident on particular solid state detectors. These results refer to electric fields between 250 and 2500 V/cm and to temperatures of 300°K, 185°K and 77°K.

Experimental results on the drift velocity of hot carriers in silicon and associated anisotropic effects

Abstract In the present work an experimental apparatus is described and experimental results are presented on the drift velocity of electrons and holes in silicon in the 2·5–12 kV/cm electric field range and at several temperatures between 300° and 77°K. Moreover, at temperatures near 77°K, an anisotropy effect is shown for electrons by means of samples cut in the (111) and (100) planes. After discussing the method of measurement, the experimental data are compared with the published data.

On the information available from the rise-time of the charge pulse supplied by semiconductor particle detectors

Abstract This paper shows that by measuring the collection time of the charge released in the depletion layer of a solid state radiation detector, some information can be obtained about the ionizing particle impact angle or about its range in the depletion layer. Several criteria are also given which allow for selecting the detectors suitable to obtain the above mentioned information.

Plasma time and related delay effects in solid state detectors

Abstract The initial delay in the response of surface barrier detectors to heavily ionizing particles is experimentally studied. Various experimental results are given about this delay in different detectors as a function of electric field and temperature. These results can be of particular interest in experiments requiring a time reference obtained by means of a solid state detector.

Plasma effects and charge collection time in solid state detectors

Abstract The effect of slowing down of charge collection due to the “plasma” situation created by strongly ionizing particles incident on a solid state detector is theoretically examined. The mathematical formulation of the problem leads to a system of partial differential equations which is numerically solved. The theoretical previsions obtained in this way for different detectors and for various ionizing particles and temperatures are in fine agreement with the experimental results.

Electron diffusion in CdTe

Electron diffusion as a function of applied field has been studied for CdTe at 300°K with the Monte Carlo technique. The high energy separation between central and satellite valleys makes the limitations on the use of the macroscopic equation of diffusion particularly severe. At fields around the threshold value for negative differential mobility, polar optical scattering produces uneven initial spreading of a delta distribution of electrons. Furthermore, at fields around and above threshold the large spread of electron velocities causes an initial diffusion much greater than that predicted by the macroscopic equation. This latter effect may be very important in small devices as, in particular, in the dynamics of Gunn domains.

PROTON--DEUTERON DISCRIMINATION WITH A SINGLE SEMICONDUCTOR DETECTOR.

Abstract A novel method is presented which permits to discriminate protons from deuterons with a single surface barrier detector and a very simple electronic circuitry. The energy measurement is not influenced by the particle discrimination system.

Experimental results on transient space charge limited currents in p-n junctions

Abstract This paper shows the first experimental evidence of transient space charge limited currents in totally depleted surface barrier p - n junctions. For this experiment surface barrier diodes excited by electrons bursts supplied by a pulsed accelerator were used. A set of theoretical and experimental data are presented on the dependence of the parameters of the current signals on the electric field and on the density of the created carriers.

Semiconductor Sensors: I—Thermoresistive Devices

This review paper concerns the state of the art in the field of semiconductor sensors based on thermoresistive effect. After an introduction to the physical principles on which these devices work, a thorough survey is made of the characteristics and applications. Finally, a critical appraisal of the situation is presented, together with some possible trends.

Semiconductor Sensors: II—Piezoresistive Devices

This paper presents a survey of the recent developments of piezoresistive sensors. First, the physical concepts which are essential for the understanding of these devices are recalled, and the characteristics and limitations (particularly temperature limitations) of semiconductor strain gauges are discussed. A further section is devoted to strain-gauge pressure transducers (the most important application of strain gauges), and, finally, possible future developments are outlined.