A New Method for the Determination of the Metal-Insulator (Semiconductor) Work Function by Photoelectric Measurements

A new method is proposed which allows a reliable determination of the metal—insulator (semiconductor) work function by a separate measurement of the total photocurrent and the current component due to internal photoexcitation in the insulator (semiconductor) film. For the purpose the usual sandwich system with a semitransparent electrode is replaced by a new type two-electrode system. The current component related to photoemission from the cathode is obtained as the difference between the total and internal photocurrent. Thus, the Fowler method applied to the emission photocurrent yields the correct value of the work function. In this way, the work functions for the systems Al—GeS and Sn-GeS are determined. It is shown that the common measuring procedure with a semitransparent electrode is unjustified and yields non-reproducible values of an apparent metal—semiconductor work function. Es wird eine neue Methode vorgeschlagen, die eine verlasliche Bestimmung der Metall—Isolator-(Halbleiter)-Austrittsarbeit durch eine getrennte Messung des Gesamtphotostromes und der Stromkomponente, die durch eine innere Photoanregung in der Isolator(Halbleiter)-Schicht hervorgerufen wird, erlaubt. Zu diesem Zweck wird das ubliche Sandwichsystem mit semitransparenten Elektroden durch ein neues Zwei-Elektrodensystem ersetzt. Die Stromkomponente, die mit der Photoemission aus der Kathode verknupft ist, wird als Differenz zwischen dem gesamten und dem inneren Photostrom erhalten. Somit liefert die auf den Emissionsphotostrom angewandte Fowler-methode den korrekten Wert der Austrittsarbeit. Auf diese Weise werden die Austrittsarbeiten fur die Systeme Al—GeS und Sn—GeS bestimmt. Es wird gezeigt, das das ubliche Mesverfahren mit der semitransparenten Elektrode unrichtig ist und keine reproduzierbaren Werte fur eine auftretende Metall—Halbleiter-Austrittsarbeit liefert.

[1]  M. Vodenicharova,et al.  Schottky and Poole‐Frenkel Mechanisms of Conductivity in Thin‐Film MeGeSMe Systems , 1980 .

[2]  S. Christov,et al.  Band Structure Effects on the Current-Voltage Characteristics of Me-GeS-Me Junctions in the Field Emission Region , 1979, January 16.

[3]  S. Christov.  Recent test and new applications of the unified theory of electron emission , 1978 .

[4]  C. Vodenicharov,et al.  Thermionic emission in the system M‐GeS‐M , 1977 .

[5]  J. Kadlec,et al.  Results and problems of internal photoemission in sandwich structures , 1976 .

[6]  S. Ikonopisov,et al.  On the Determination of the Metal‐Insulator Work Function by Photoelectric Measurements , 1975 .

[7]  J. Kadlec,et al.  Interfacial barrier height measurement from voltage dependence of the photocurrent , 1975 .

[8]  C. Vodenicharov,et al.  Kinetics of Vacuum Deposition of GeS Films , 1975 .

[9]  S. Christov,et al.  Current-field and current-temperature dependences for AlAl2O3Al junctions in the regions of thermionic, field, and TF emission , 1974 .

[10]  K. J. Binns,et al.  Analysis and computation of electric and magnetic field problems , 1973 .

[11]  J. Kadlec,et al.  Space-Charge Dependence of the Barrier Height on Insulator Thickness in Al-(Al-Oxide)-Al Sandwiches , 1972 .

[12]  C. Mead,et al.  Barrier Energies in MIM Structures from Photoresponse: Effect of Scattering in the Insulating Film , 1972 .

[13]  J. Kadlec,et al.  Temperature dependence of the barrier height in Al‐(Al‐oxide)‐Al junctions, observed by photoelectric measurements , 1971 .

[14]  L. Esaki,et al.  HIGH‐FIELD PHOTOCONDUCTIVITY OF AMORPHOUS GeTe and GeSe FILMS , 1970 .

[15]  R. Fowler,et al.  The Analysis of Photoelectric Sensitivity Curves for Clean Metals at Various Temperatures , 1931 .