Surface conductance of germanium cleaved in liquid nitrogen

The surface states of germanium have been investigated by measuring the change in conductance occurring upon cleavage of a (Ill) plane, in liquid nitrogen, Experiments are carried out with n-type samples whose donor concentrations vary from 10 13 to 10 18 /cm 3 • D-c measurements are made on p-n-p structures; upon cleavage ~ a po-type channel is formed across the surface, It is found that at the low temperature of the experiment and with the large electric field existing at the surface, quantum mechanical effects arise in the space charge region. A method of analysis is presented with a pseudo two-dimensi.onal space charge region, and applied for two extreme values of the hole mobility, The results are related to two models of the surface energy spectrum for the excess electrons: 1) a discrete level with 1,44 x 10 15 states/cni 2 , 2) a 20 ev wide band of levels with '7,22 x 10 13 states/cm 2 -ev. It is shown that the heavy holes in the space charge region are more likely to move with a mobiLity close to their bulk mobility, Acceptor-like surface states are found to lie 0,06 +- 0,03 ev above the first allowed level for heavy holes. It is not possible to decide on the distribution of states,

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Proix, Francoise Roberte Fernande

Contributors dc:contributor

• Handler, Paul

• germanium surface states
• conductance
• cleavage in liquid nitrogen
• p-n-p structures

Statement dc:rights

• 1966 Francoise Roberte Fernande Proix

Language dc:language

en

Identifier

6124331

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25067