Accession Number:

ADA276159

Title:

Experimental and Theoretical Studies of Hydrogenated Amorphous Semiconductor Alloys and Superlattices

Descriptive Note:

Final rept. 15 Sep 1989-14 Dec 1993

Corporate Author:

PUERTO RICO UNIV RIO PIEDRAS

Report Date:

1994-02-04

Pagination or Media Count:

78.0

Abstract:

We developed the photocarrier grating technique for carrier mobility- lifetime products micro-Tau measurements. Applying this technique to hydrogenated amorphous silicon a-SiH, we obtained micro-Tau values ranging from 10exp-8 to 10exp-5 sq cmV for the majority and 10exp-10 - 10exp-8 for the minority carrier. This served as a basis for quality evaluation of prepared by different methods. We established that the dominant recombination mechanism is the defect pool mechanism. Using the semiconductor-electrolyte system, we studied the density of localized states in a-Si-H and compared it to crystalline silicon. We found in a-SiH an overall density of localized states in 10exp-18 cu cm. In crystalline Si only surface states were found, of an overall density of 10exp-12 sqcm. The sq cm states are centered around 0.2 eV the conduction band edge. The transport properties of two other disordered systems that may be relevant to a-Si-H were studied theoretically. These systems consists of metal cermets and of small colloidal suspensions.

Subject Categories:

  • Physical Chemistry
  • Electrical and Electronic Equipment
  • Metallurgy and Metallography
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE