A248

Surface Science 170 (1986) 501-505

North-Holland. Amsterdam

SO I

INELASTIC ELECTRON SCATTERING BY COLLECTIVE CHARGE DENSITY EXCITATIONS AT THE SURFACE OF A SEMICONDUCTOR SUPERLATTICE Pawel HAWRYLAK. Ji-Wei WU and J.J. QUINN

Rrmr~t~ 1 r,,,‘cr.\,,,~. Pr~~/~&~~c~e, Rhode Idmd 07V/.?, 1 S 1

Received 10 4ugust 19X5: accepted for publication 13 September lYX5

Uung hnear response theory and the dtagqnai approxtmatmn we calculate exactly and

analyticallp surface rehponhe of a semt-infinite semiconductor superlattlce to an electron moving in

the vacuum. This response determine\ the scattering process. The electron energ) loss \ptxtrum

due to surface mtra- and intersuhband plasmon\ i\ predxtrd for the ftrst time.

506 Surface Scxncr 170 ( IYXh) 506~~510

North-Holland. 4mstrrdam

LATERAL SURFACE MAGNETOPLASMON IN A SEMICONDUCTOR SUPERLATTICE AND EDGE MAGNETOPLASMON IN A TWO-DIMENSIONAL ELECTRON GAS

J.-W. WU. Pawel HAWRYLAK. Gunnar EL.IASSON and J.J. QUINN

Phwc:s Depurmmt. Brown L’nrrvnrtr, Prodcvwt’, Rhmk Irlmd 02YlJ. 1 S/t

Recelwd 10 August 1985: accepted for puhlicatlon 13 Septcmher 19X5

The charge density collective excltatlon aswunted with the lateral \urfacc of ‘t vx~~cunductor

superlattice I:, btudied for the first ttme. An approximate dl\peralon rclatwn of the \urface plasm:1

and magnetoplasma modes I.\ obtained from an approximate wlution to the w;r\e equ;ttt<w

Surface Sctrnce 170 ( 19X6) 5 I l-5 19

North-Holland, Amsterdam

511

TIME-RESOLVED PHOTOLUMINESCENCE FROM HOT TWO-DIMENSIONAL CARRIERS IN GaAs-GaAIAs MQWS

J.F. RYAN, R.A. TAYLOR and A.J. TURBERFIELD

Clrrendm Lohorcrtor~~. C’nrwr.rrt~~ of Ovl*ml. Purl, 5 R~xui. O\/nnl Ok’1 .iPl 1 h

and

J.M. WORLOCK

Bdf (‘~nlnl~l~~(,ut~on.).~n.s Resrurch. Holmdel, .Ven, Jrrvei 0”1?. ~‘s.4

Received 5 August 19X5; accepted for publicatmn 13 September 19X5

Ptcosecond time-resolved measurement\ of lummexence from hot carrlrrs confined III

C&Ah-GaAIAs multiple quantum wells show that energy loss rates art‘ wh\tantlall> aloaer than those predicted for 2D carriers. WC rebieu our recent experiments and present rehult\ for

photoexcitatlon of (1) GaAs layers only. (2) both GaAs and GaAIA\ layers. We compare the

energy loss rates in samples with different well wtdths. Finally. we present measurements of hot

2D carrier relaxation in the presence of high magnetic flrlds: at IOU field\ the snerg\ Itw rate I\ reduced. but for B ) 9 T we observe a wpid increase