Investigation of negative resistance induced by directional scattering in a two dimensional electron gas

Abstract

Yakin geçmiste yüksek hareketlilikli iki boyutlu iletkenlerin üretilmesimümkün olmustur. Bu iki boyutlu iletkenlerde yapilan çalismalar, ikisi Nobel ödülü alanbirçok yeni fiziksel olayin kesfine yolaçmistir. Boyut sayisindaki azalmayla elektronsaçilma nitelikleri çok degismekte ve elektron-elektron çarpisma açisi çok daralmaktadir.Yakin zamanlarda, bu tür yöneltilmis saçilmalarin iki boyutta, elektron çogalmasina vemutlak eksi direnç elde edilmesinde kullanilabilecegi gösterilmistir. Deneyler aygitboyutlari daha da küçüldügünde bu etkinin güçlenecegini göstermekte ve yeni bir THzradyasyon kaynagi yapiminda kullanma olasiligini göstermektedir.Bu tezin ana amaci, deneysel olarak daha da küçültülmüs, elektronçogaltmaaygiti üretme metodu gelistirmek ve üretilen aygitlarin elektriksel özellikleriniboyutlarina bagli olarak incelemektir. Bu yeni üretim metodu aygit boyutlarinin mikronalti büyüklüklere indirilebilmesini mümkün kilmaktadir. Bu çalismada üretilen 2 mikronbaz uzunlugundaki aygitin akim transfer oranin 5'e kadar çikabildigi gözlenmistir.This document was created with Win2PDF available at http://www.win2pdf.com.The unregistered version of Win2PDF is for evaluation or non-commercial use only.This page will not be added after purchasing Win2PDF.

In the last decades, it became possible to manufacture high mobility two-dimensional conductors. The study of electron transport in such two dimensionalconductors has led to discovery of many new physical phenomena, two of which wereawarded with Nobel prizes. The reduction in the dimensions of a conductor drasticallychanges the scattering properties of carriers. Intercarrier scattering angle is also severelyreduced in two dimensions. Recently, it was shown that this kind of directional scatteringcan be exploited to achieve electron multiplication and absolute negative resistance in athree terminal configuration. Experimental results suggest that such an effect shouldboost as the device size shrinks and can be useful to fabricate compact high frequencysources that are not yet within the reach of conventional semiconductor devices.The purpose of this thesis is to extend further the experimental study of suchphenomena, and in particular, to understand its dependence on the device size. For this anew fabrication method has been developed. This method gives a greater flexibility toshrink the device size down to sub-microns. The new generation of fabricated devicesproduce high electron multiplication ratios up to 5.This document was created with Win2PDF available at http://www.win2pdf.com.The unregistered version of Win2PDF is for evaluation or non-commercial use only.This page will not be added after purchasing Win2PDF.